Soccer Football - International Friendly - Wales v Trinidad and Tobago - The Racecourse, Wrexham, Britain - March 20, 2019 Former Wales' player John Hartson at half time REUTERS/Rebecca Naden

Soccer Football - Champions League - Celtic vs Paris St Germain - Celtic Park, Glasgow, Britain - September 12, 2017 Former Celtic footballers John Hartson, Chris Sutton and Henrik Larsson before the match Action Images via Reuters/Lee Smith

Soccer Football - Champions League - Celtic vs Paris St Germain - Celtic Park, Glasgow, Britain - September 12, 2017 Former Celtic footballers John Hartson, Chris Sutton and Henrik Larsson before the match Action Images via Reuters/Lee Smith

Soccer Football - Champions League - Celtic vs Paris St Germain - Celtic Park, Glasgow, Britain - September 12, 2017 Former Celtic footballers John Hartson, Chris Sutton and Henrik Larsson before the match Action Images via Reuters/Lee Smith

Britain Soccer Football - Swansea City v Everton - Premier League - Liberty Stadium - 6/5/17 Ian Wright and John Hartson working as pundits with Swansea City's Nathan Dyer (L) before the match Action Images via Reuters / John Sibley Livepic EDITORIAL USE ONLY. No use with unauthorized audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 45 images, no video emulation. No use in betting, games or single club/league/player publications. Please contact your account representative for further details.

Britain Soccer Football - Swansea City v Everton - Premier League - Liberty Stadium - 6/5/17 Ian Wright and John Hartson working as pundits before the match Action Images via Reuters / John Sibley Livepic EDITORIAL USE ONLY. No use with unauthorized audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 45 images, no video emulation. No use in betting, games or single club/league/player publications. Please contact your account representative for further details.

Football Soccer - Sweden v Wales - International Friendly - Friends Arena, Stockholm, Sweden - 5/6/16
Former Wales footballer John Hartson (L)
Action Images via Reuters / Andrew Boyers

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Arsenal's John Hartson (R) celebrates after scoring the opening goal during their first Premiership match of the season against West Ham, August 17, 1996. Arsenal won the match 2-0. REUERS/Ian Waldie (BRITAIN)

Blackburn Rovers Lars Bohinen collides with Arsenal's John Hartson during their Premier League match at Highbury, November 26, 1995. The match drew 0-0. REUTERS/Russell Boyce

Celtic's John Hartson (L) and Bobo Balde (R) are challenged by Glasgow Rangers' Dado Prso (back left) and Marvin Andrews (back right) for the ball during their Scottish Premiere League soccer match at Ibrox Stadium in Glasgow February 12, 2006. REUTERS/Gordon Jack

Celtic's John Hartson (L) and Bobo Balde (R) are challenged by Glasgow Rangers' Dado Prso (back left) and Marvin Andrews (back right) for the ball during their Scottish Premiere League soccer match at Ibrox Stadium in Glasgow February 12, 2006. REUTERS/Gordon Jack

Clyde's Craig McKeown (L) celebrates his team's second goal as Celtic's John Hartson (2nd L), Roy Keane (C) Neil Lennon (2nd R) and Ross Wallace stand in disbelief during their Scottish Cup third round soccer match at Broadwood Park in Cumbernauld January 8, 2006. REUTERS/Gordon Jack

Celtic's Roy Keane (2nd L), John Hartson (3rd L) and Neil Lennon (3rd R) watch as Clyde's Eddie Malone (not pictured) scores past Artur Boruc (bottom R) during their Scottish Cup third round soccer match at Broadwood Park in Cumbernauld January 8, 2006. Clyde won the match 2-1. REUTERS/Gordon Jack

Celtic's John Hartson (L) fights for the ball with Hearts' Steven Pressley during their Scottish Premier League soccer match at Tynecastle stadium in Edinburgh January 1, 2006. REUTERS/Tony Marsh

Celtic's John Hartson celebrates victory over Hearts following their Scottish Premier League soccer match at Tynecastle stadium in Edinburgh January 1, 2006. Celtic won the match 3-2. REUTERS/Tony Marsh

Celtic's John Hartson celebrates victory over Hearts following their Scottish Premier League soccer match at Tynecastle stadium in Edinburgh, January 1, 2006. Celtic won the match 3-2. REUTERS/Tony Marsh

Celtic's Aiden McGeady is surrounded by Mo Camara (top), John Hartson (R), Bobo Balde (C), Stephen Mc Manus (L) and Alan Thompson (8) as they celebrate after he scored against Glasgow Rangers during their Scottish Premier Divison soccer match at Celtic Park in Glasgow November 19, 2005. REUTERS/Jeff J Mitchell

Celtic's Aiden McGeady (46) is surrounded by Mo Camara (C), John Hartson (R), Bobo Balde (2nd R), Stephen McManus and Alan Thompson as they celebrate after scoring against Rangers during their Scottish Premier Division soccer match at Celtic Park in Glasgow November 19, 2005. REUTERS/Jeff J Mitchell

Rangers goal keeper Ronald Waterreus looks back into the net after Celtic's John Hartson scored during their Scottish Premier Division soccer match at Celtic Park in Glasgow November 19, 2005. Celtic won the match 3-0. REUTERS/Jeff J Mitchell

Celtic's John Hartson celebrates after scoring against the Rangers during their Scottish Premier Division soccer match at Celtic Park in Glasgow November 19, 2005. REUTERS/Jeff J Mitchell

Celtic's John Hartson (back) tackles Rangers Julian Rodriguez during the CIS Insurance Cup quarter-final at Celtic Park in Glasgow November 9, 2005. REUTERS/Jeff J Mitchell

Goalkeeper Paul Jones of Wales (L) punches the ball clear from Northern Ireland's Colin Murdock (R) and Michael Duff (2nd L) as team mates John Hartson and Mark Delaney (2nd R) defend during their World Cup 2006, Group Six qualifying soccer match at Windsor Park in Belfast, October 8, 2005. Wales secured their first competitive win in more than two years with a 3-2 victory over Northern Ireland in their qualifier at Windsor Park on Saturday. REUTERS/Darren Staples

John Hartson of Wales (R) fails to score past Northern Ireland's Maik Taylor (L) from the penalty spot during their World Cup 2006, Group Six qualifying soccer match at Windsor Park in Belfast, October 8, 2005. REUTERS/Darren Staples

England's captain Beckham shakes hands with Hartson of Wales after World Cup 2006 Group Six qualifying match in Cardiff. England's captain David Beckham (R) shakes hands with John Hartson (L) of Wales after their World Cup 2006, Group Six, qualifying soccer match at the Millennium stadium in Cardiff, Wales, September 3, 2005. England won the match 1-0. REUTERS/Eddie Keogh

England's captain Beckham celebrates at final whistle as Hartson of Wales walks off after World Cup 2006 qualifying match in Cardiff. England's captain David Beckham (R) celebrates at the final whistle as John Hartson (L) of Wales walks off after their World Cup 2006, Group Six, qualifying soccer match at the Millennium stadium in Cardiff, Wales, September 3, 2005. England won the match 1-0. REUTERS/Eddie Keogh

Celtic's Hartson celebrates after scoring against Dundee United during their Scottish Premier division soccer match at Celtic Park in Glasgow. Celtic's John Hartson celebrates after scoring against Dundee United during their Scottish Premier division soccer match at Celtic Park in Glasgow August 6, 2005.REUTERS/Jeff J Mitchell

Celtic's coach Gordon Strachan shouts to his palyers during their Scottish Premier division soccer match against Dundee United at Celtic Park. Celtic's coach Gordon Strachan shouts to his players during their Scottish Premier League soccer match against Dundee United at Celtic Park in Glasgow August 6, 2005. Celtic enjoyed their first league win under new boss Strachan with a 2-0 home success over Dundee United thanks to goals in each half from John Hartson and Craig Beattie. REUTERS/Jeff J Mitchell

Celtic's Hartson celebrates after scoring against Dundee United during Scottish Premier division soccer match at Celtic Park in Glasgow. Celtic's John Hartson celebrates after scoring against Dundee United during their Scottish Premier division soccer match at Celtic Park in Glasgow August 6, 2005.REUTERS/Jeff J Mitchell

Celtic's John Hartson (L) walks off the pitch as Artmedia Petrzalka's players celebrate at the end of their UEFA Champions League second qualifying round, second leg soccer match at Celtic Park in Glasgow August 2, 2005. Celtic lost 5-4 on aggregate. REUTERS/Jeff J Mitchell JJM/RD/NL

Celtic's Hartson celebrates his first goal with team mate McManus in their Scottish Premier League soccer match against Motherwell at the Fir Park stadium in Glasgow. Celtic's John Hartson (L) celebrates his first goal with team mate Stephen McManus in their Scottish Premier League soccer match against Motherwell at the Fir Park stadium in Glasgow on July 30, 2005. Celtic, hammered 5-0 by Artmedia Petrzalka in midweek, suffered fresh misery when they blew a 3-1 lead to draw 4-4 at Motherwell in the opening game of the season in the Scottish Premier League on Saturday. REUTERS/ Gordon Jack

Celtic's Hartson scores his second goal against Motherwell in their Scottish Premier League soccer match at the Fir Park stadium in Glasgow. Celtic's John Hartson (2nd R) scores his second goal of the match to make it 0-2 against Motherwell in their Scottish Premier League soccer match at the Fir Park stadium in Glasgow on July 30, 2005. Celtic, hammered 5-0 by Artmedia Petrzalka in midweek, suffered fresh misery when they blew a 3-1 lead to draw 4-4 at Motherwell in the opening game of the season in the Scottish Premier League on Saturday. REUTERS/ Gordon Jack

Motherwell's goalkeeper Marshall fails to save Celtic's Hartson's first goal of the match in their Scottish Premier League soccer match at the Fir Park stadium in Glasgow. Motherwell's goalkeeper Gordon Marshall (L) fails to save Celtic's John Hartson's first goal of the match in their Scottish Premier League soccer match at the Fir Park stadium in Glasgow on July 30, 2005. Celtic, hammered 5-0 by Artmedia Petrzalka in midweek, suffered fresh misery when they blew a 3-1 lead to draw 4-4 at Motherwell in the opening game of the season in the Scottish Premier League on Saturday. REUTERS/ Gordon Jack

Celtic's Hartson celebrates his first goal with team mate McManus in their Scottish Premier League soccer match against Motherwell at the Fir Park stadium in Glasgow. Celtic's John Hartson (L) celebrates his first goal with team mate Stephen McManus in their Scottish Premier League soccer match against Motherwell at the Fir Park stadium in Glasgow on July 30, 2005. The match finished 4-4. REUTERS/ Gordon Jack

Celtics' Hartson celebrates with team mate Lennon during Scottish Premier League match against Motherwell at Firpark. Celtics' John Hartson (L) celebrates his second goal with team mate Neil Lennon during a Scottish Premier League soccer match against Motherwell at Firpark, Motherwell, July 30, 2005. REUTERS/Gordon Jack

Celtics' Hartson celebrates with team mate Lennon during Scottish Premier League match against Motherwell at Firpark. Celtics' John Hartson (L) celebrates his second goal with team mate Neil Lennon during a Scottish Premier League soccer match against Motherwell at Firpark, Motherwell, July 30, 2005. REUTERS/Gordon Jack

Celtic's John Hartson (C) is tackled by Dundee United's Alan Archibald (R) in the Scottish Cup soccer final at Hampden Park in Glasgow, May 28, 2005. REUTERS/Matthew Roberts mr/TC

Carl Fletcher (R) and John Hartson of Wales react after Austria's Ivica Vastic (not pictured) scored during their Group Six World Cup qualifying soccer match at the Millennium Stadium, Cardiff, March 26, 2005. Austria won the match 2-0. REUTERS/Mike Finn-Kelcey MFK/AA

Celtic's Bobo Balde celebrates with John Hartson and Chris Sutton after scoring against Dundee during their Scottish Premier League soccer match. Celtic's Bobo Balde celebrates with John Hartson (L) and Chris Sutton (R) after scoring against Dundee during their Scottish Premier League soccer match at Celtic Park in Glasgow March 2,2005.Celtic won the match 3-0. REUTERS/Jeff J Mitchell

Celtic's John Hartson jumps for the ball with Dundee's Robert Mann during their Scottish Premier League soccer match at Celtic Park. Celtic's John Hartson jumps for the ball with Dundee's Robert Mann (L) during their Scottish Premier League soccer match at Celtic Park in Glasgow March 2, 2005. REUTERS/Jeff J Mitchell

Celtic's John Hartson is tackled by Rangers' Gregory Vignal during their Scottish Premier League soccer match at Celtic. Celtic's John Hartson (R) is tackled by Rangers' Gregory Vignal of France during their Scottish Premier League soccer match at Celtic Park in Glasgow February 20, 2005. Rangers won the match 2-0. REUTERS/Jeff J Mitchell

Celtic's Hartson beaten to the ball by Rangers' Ferguson and Kyrgiakos during their Scottish Premier League soccer match in Glasgow. Celtic's John Hartson (R) is beaten to the ball by Rangers' Barry Ferguson (2nd L) and Sotirois Kyrgiakos (L) during their Scottish Premier League soccer match at Celtic Park in Glasgow February 20, 2005.Rangers won the match 2-0. REUTERS/Jeff J Mitchell

Celtic's John Hartson celebrates with team mates Chris Sutton (L) and Bobo Balde (R) after scoring against Dunfermline during their Scottish Cup 4th round soccer match at East End Park in Dunfermline, February 6, 2005. Celtic won the match 3-0. REUTERS/Jeff J Mitchell JJM/JD/SM

Celtic's Hartson competes for the ball with Dunfermline's Mason during their Scottish Cup soccer match at Dunfermline. Celtic's John Hartson (L) competes for the ball with Dunfermline's Gary Mason during their Scottish Cup 4th round soccer match at East End Park in Dunfermline, February 6, 2005. Celtic won the match 3-0. REUTERS/Jeff J Mitchell

Celtic's striker John Hartson celebrates after scoring against Dunfermline in the Scottish Cup 4th round soccer match at East End Park in Dunfermline, February 6, 2005. REUTERS/Jeff J Mitchell JJM/JD

Kilmarnock's Lilley competes for the ball with Celtic's Hartson during their Scottish Premier League soccer match. Kilmarnock's David Lilley competes for the ball with Celtic's John Hartson during their Scottish Premier League soccer match at Rugby Park in Kilmarnock January 30, 2005. Celtic won the match 1-0. REUTERS/Jeff J Mitchell

Kilmarnock's Invincible competes for the ball with Celtic's John Hartson during their Scottish Premier League soccer match. Kilmarnock's Danny Invincible competes for the ball with Celtic's John Hartson (R) during their Scottish Premier League soccer match at Rugby Park in Kilmarnock January 30, 2005. REUTERS/Jeff J Mitchell

Celtic's John Hartson competes for the ball with Livingston's Dorado during their Scottish Premier League soccer match at Celtic Park. Celtic's John Hartson competes for the ball with Livingston's Emanuel Dorado (R) during their Scottish Premier League soccer match at Celtic Park in Glasgow January 2, 2005. Celtic won the match 2-1. REUTERS/Jeff J Mitchell

Celtic's John Hartson (top) jumps over AC Milan's Massimo Ambrosini during their Champions League Group F soccer match at Celtic Park in Glasgow, December 7, 2004. The match ended a 0-0 draw. REUTERS/Jeff J Mitchell JJM/MD

Celtic's John Hartson (R) is tackled by AC Milan's Alessandro Nesta during their Champions League Group F soccer match at Celtic Park in Glasgow, December 7, 2004. REUTERS/Jeff J Mitchell JJM/MD

Celtic's John Hartson (R) is tackled by AC Milan's Paolo Maldini during their Champions League Group F soccer match at Celtic Park in Glasgow, December 7, 2004. REUTERS/Jeff J Mitchell JJM/MD

Barcelona's Carles Puyol (R) fights for the ball with Celtic's John Hartson (L) during their Champions League Group F soccer match at Nou Camp stadium in Barcelona November 24, 2004. REUTERS/Albert Gea AG/SM

Celtic FC goalkeeper Magnus Hedman celebrates goal by team mate John Hartson against FC Barcelona during Champions League group F soccer match in Barcelona. Celtic FC goalkeeper Magnus Hedman celebrates a goal by his team mate captain John Hartson against FC Barcelona during their Champions League group F soccer match at Nou Camp stadium in Barcelona November 24, 2004. REUTERS/Gustau Nacarino

Celtic's John Hartson celebrates his goal against FC Barcelona during Champions League Group F soccer match at Nou Camp stadium in Barcelona. Celtic's John Hartson celebrates his goal against FC Barcelona during their Champions League Group F soccer match at the Nou Camp stadium in Barcelona November 24, 2004. REUTERS/Albert Gea

Celtic FC John Hartson gestures during his press conference at Nou Camp stadium, in Barcelona, Spain, November 23, 2004. FC Barcelona and Celtic FC will play their Champions league group F second leg match at Nou Camp stadium on Wednesday. REUTERS Gustau Nacarino GN/ABP

Celtic FC forward John Hartson controls the ball during the training session at the Nou Camp stadium in Barcelona November 23, 2004. FC Barcelona and Celtic FC will play their Champions League group F second leg soccer match here on Wednesday. REUTERS/Gustau Nacarino GN/GB

Celtic's John Hartson jumps for the ball with Shakhtar Donetsk's Mariusz Lewandowski during Champions League soccer match. Celtic's John Hartson jumps for the ball with Shakhtar Donetsk's Mariusz Lewandowski (L) during their Champions League Group F match at Celtic Park in Glasgow November 2, 2004. REUTERS/Jeff J Mitchell

Celtic's John Hartson competes for the ball with Motherwell's Phil O'Donnell during their Scottish Premier League soccer match. Celtic's John Hartson (R) competes for the ball with Motherwell's Phil O'Donnell during their Scottish Premier League soccer match at Fir Park stadium in Motherwell, October 30, 2004. Celtic won the match 3-2. REUTERS/Jeff J Mitchell

Celtic's McGeady celebrates after scoring against Motherwell in a Scottish Premier League soccer match in Motherwell. Celtic's Aidan McGeady celebrates with John Hartson (R) after scoring against Motherwell during their Scottish Premier League soccer match at Fir Park stadium in Motherwell, October 30, 2004. REUTERS/Jeff J Mitchell

Shakhtar Donetsk' Anatoliy Tymoshchuk (R) challenges John Hartson of Celtic during their Champions League Group F soccer match in Donetsk, October 20, 2004. REUTERS/Gleb Garanich GG/ACM

Hartson of Wales battles for the ball with England's Campbell and Butt in their World Cup qualifier at Old Trafford. John Hartson (R) of Wales battles for the ball with England's Sol Campbell (C) and Nicky Butt (bottom) in their World Cup, European Zone, Group Six qualifier at Old Trafford, Manchester, October 9, 2004. REUTERS/Mike Finn-Kelcey