Mercedes Formula One driver Lewis Hamilton of Britain is seen in the box during the first free practice session for the Italian F1 Grand Prix in Monza. Images of athletes with tattoos, September 4, 2015. REUTERS/Max Rossi 

AS Roma's Radja Nainggolan stretches before the start of his Italian Serie A soccer match against Inter Milan at the Olympic stadium in Rome November 30, 2014. REUTERS/Alessandro Bianchi 

A tattoo is seen on an AS Roma player before the start of their Italian Serie A soccer match against Udinese at the Friuli stadium in Udine, January 6, 2015. REUTERS/Stefano Rellandini 

Football - England Training - St George's Park - 4/9/15
General view of England's Jonjo Shelvey's tattoos on his legs during training. Action Images via Reuters / Lee Smith
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The tattoo of Sparkle Mcknight of Trinidad and Tobago id seen as she competes in the women's 400 metres hurdles semi-final during the 15th IAAF World Championships at the National Stadium in Beijing, China August 24, 2015. REUTERS/Lucy Nicholson 

Paris St Germain's Zlatan Ibrahimovic walks out of the pitch at the end of the French Ligue 1 soccer match against En Avant Guingamp at Parc des Princes stadium in Paris, France May 8, 2015. REUTERS/Gonzalo Fuentes 

AC Milan David Beckham celebrates at the end of the match against Juventus during their Serie A soccer match at Olympic stadium in Turin, January 10, 2010. AC Milan won 3-0. REUTERS/Stefano Rellandini 

Sevilla's Victor Machin "Vitolo" (R) is congratulated by teammate Ever Banega after scoring against Levante during their Spanish First Division soccer match at Ramon Sanchez Pizjuan stadium in Seville, November 9, 2014. REUTERS/Marcelo del Pozo 

Aston Villa's James Collins leaves the pitch with a head injury during their English Premier League soccer match against Burnley at Villa Park in Birmingham, central England, February 21, 2010. REUTERS/Darren Staples 

Paris St Germain's Ezequiel Lavezzi celebrates after scoring against Saint Etienne during their French Cup semi-final soccer match at the Parc des Princes stadium in Paris April 8, 2015. REUTERS/Benoit Tessier 

Barcelona's Neymar walks during a training session at Ciutat Esportiva Joan Gamper in Sant Joan Despi, near Barcelona April 10, 2015. REUTERS/Gustau Nacarino 

Juventus' Arturo Vidal celebrates at the end of their Serie A soccer match against Sampdoria at the Marassi stadium in Genoa, Italy, May 2, 2015. REUTERS/Giorgio Perottino 

David Beckham attends a press conference to mark his 10 years as a UNICEF Goodwill Ambassador, at Google's headquarters in central London, February 9, 2015. REUTERS/Peter Nicholls 

Barcelona's Lionel Messi shows the Best Player UEFA 2015 Award to the crowd before their Spanish first division soccer match against Malaga at Camp Nou stadium in Barcelona, Spain, August 29, 2015. REUTERS/Albert Gea 

Matthieu Rosset of France jumps during the men's 3m springboard final at the Aquatics World Championships in Kazan, Russia July 31, 2015. REUTERS/Hannibal Hanschke 

Ilya Shkurenev of Russia reacts after his 1500 metres heat of the men's decathlon during the 15th IAAF Championships at the National Stadium in Beijing, China, August 29, 2015. REUTERS/Damir Sagolj 

A tattoo is seen on the back of Johannes Vetter of Germany as he competes in the men's javelin throw final during the 15th IAAF World Championships at the National Stadium in Beijing, China, August 26, 2015. REUTERS/David Gray 

Miami Heat forward Chris Andersen stands on the court during player introductions before their NBA basketball game against the Boston Celtics in Boston, Massachusetts, March 18, 2013. REUTERS/Brian Snyder 

A tattoo with the number of his car is seen behind the ear of the Mercedes Formula One driver Lewis Hamilton of Britain in the paddock at the Monaco F1 Grand Prix May 20, 2015. REUTERS/Max Rossi 

A tattoo is seen on the back of Timea Bacsinszky of Switzerland as she reacts during her women's semi-final match against Serena Williams of the U.S. at the French Open tennis tournament at the Roland Garros stadium in Paris, France, June 4, 2015. REUTERS/Gonzalo Fuentes 

Former world heavyweight champion Mike Tyson arrives for the screening of U.S. director James Toback's documentary film "Tyson" at the 61st Cannes Film Festival May 16, 2008. REUTERS/Jean-Paul Pelissier 

Bruno Fratus of Brazil prepares prior to the men's 50m freestyle final at the Aquatics World Championships in Kazan, Russia, August 8, 2015. REUTERS/Hannibal Hanschke 

The words "blood" and "sweat" are seen tattooed on the hands of former NFL New England Patriots tight end Aaron Hernandez, as he appears in court for a motion hearing in Attleborough, Massachusetts, August 30, 2013. REUTERS/Dominick Reuter 

Moldova's Vasilii Belous (L) sports a tattoo as he fights against Tanzania's Selemani Kidunda during the men's welter (69kg) Round of 32 boxing match at ExCeL venue during the London 2012 Olympic Games July 29, 2012. REUTERS/Murad Sezer 

A tattoo is pictured on the arm of Fiorentina's Jasmin Kurtic during his Europa League Group K soccer match against Guingamp at the Roudourou stadium in Guingamp, November 27, 2014. REUTERS/Stephane Mahe 

Matthieu Rosset of France jumps during the men's 3m springboard final at the Aquatics World Championships in Kazan, Russia July 31, 2015. REUTERS/Hannibal Hanschke