Britain's Prince Harry is embraced by singer Rihanna before taking an HIV test to highlight World AIDS Day in Bridgetown, Barbados December 1, 2016. REUTERS/Antonio Miller/Barbados Government Information Service (BGIS)/POOL

Britain's Prince Harry is embraced by singer Rihanna before taking an HIV test to highlight World AIDS Day in Bridgetown, Barbados December 1, 2016. REUTERS/Antonio Miller/Barbados Government Information Service (BGIS)/POOL

Britain's Prince Harry takes an HIV test alongside singer Rihanna to highlight World AIDS Day in Bridgetown, Barbados December 1, 2016. REUTERS/Antonio Miller/Barbados Government Information Service (BGIS)/POOL

Britain's Prince Harry takes an HIV test alongside singer Rihanna to highlight World AIDS Day in Bridgetown, Barbados December 1, 2016. REUTERS/Antonio Miller/Barbados Government Information Service (BGIS)/POOL

Britain's Prince Harry takes an HIV test alongside singer Rihanna to highlight World AIDS Day in Bridgetown, Barbados December 1, 2016. REUTERS/Antonio Miller/Barbados Government Information Service (BGIS)/POOL

Britain's Prince Harry takes an HIV test alongside singer Rihanna to highlight World AIDS Day in Bridgetown, Barbados December 1, 2016. REUTERS/Antonio Miller/Barbados Government Information Service (BGIS)/POOL TPX IMAGES OF THE DAY

The footwear of Britain's Prince Harry (R) and Barbadian singer Rihanna are seen as they take part in a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Britain's Prince Harry (L) stands next to Barbadian singer Rihanna and Barbados' Prime Minister Freundel Stuart, as he waves towards the audience while taking part in a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados, November 30, 2016. REUTERS/Adrees Latif TPX IMAGES OF THE DAY

Barbadian Prime Minister Freundel Stuart (R), Britain's Prince Harry (C) and singer Rihanna stand for the national anthem ahead of a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Barbadian Prime Minister Freundel Stuart (R) reacts to the audience while sitting next to Britain's Prince Harry (C) and singer Rihanna (L) during a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Barbadian singer Rihanna (L), sitting next to Britain's Prince Harry, reacts to fans ahead of a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Barbadian singer Rihanna (L), sitting next to Britain's Prince Harry, applauds a speaker ahead of a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Britain's Prince Harry (C), Barbadian singer Rihanna (L) and Prime Minister Freundel Stuart stand during a prayer ahead of a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Britain's Prince Harry (C), Barbadian singer Rihanna (L) and Prime Minister Freundel Stuart applaud the recitation of the national anthem during a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Britain's Prince Harry (C) smiles with Barbadian singer Rihanna (L) and Prime Minister Freundel Stuart during a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Britain's Prince Harry (R), sitting next to Barbadian singer Rihanna, signs towards the audience while taking part in a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Britain's Prince Harry (R), sitting next to Barbadian singer Rihanna, signs towards the audience while taking part in a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados November 30, 2016. REUTERS/Adrees Latif

Britain's Prince Harry (R), sitting next to Barbadian singer Rihanna, signs towards the audience while taking part in a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados, November 30, 2016. REUTERS/Adrees Latif

Barbadian singer Rihanna waves towards the audience while taking part in a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados, November 30, 2016. REUTERS/Adrees Latif

Britain's Prince Harry (L) stands next to Barbadian singer Rihanna and Barbados' Prime Minister Freundel Stuart, as he waves towards the audience while taking part in a concert in Bridgetown to commemorate the 50th independence anniversary of Barbados, November 30, 2016. REUTERS/Adrees Latif

Singer Rihanna arrives to atttend the Italian designer Maria Grazia Chiuri Spring/Summer 2017 women's ready-to-wear collection for fashion house Dior during Fashion Week in Paris, France September 30, 2016. REUTERS/Gonzalo Fuentes

Singer Rihanna arrives to atttend the Italian designer Maria Grazia Chiuri Spring/Summer 2017 women's ready-to-wear collection for fashion house Dior during Fashion Week in Paris, France September 30, 2016. REUTERS/Gonzalo Fuentes

Drake presents Rihanna with the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson TPX IMAGES OF THE DAY

Rapper Drake escorts singer Rihanna as she walks offstage after accepting the Michael Jackson Video Vanguard Award at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna accepts the Michael Jackson Video Vanguard Award on at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna accepts the Michael Jackson Video Vanguard Award on at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna (C) performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Drake speaks with Rihanna after presenting her with the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna (C) performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Drake speaks with Rihanna after presenting her with the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna accepts the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna accepts the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna accepts the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Drake presents Rihanna with the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna (C) performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Drake presents Rihanna with the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Drake presents Rihanna with the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Drake presents Rihanna with the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna (C) performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Drake presents Rihanna with the Michael Jackson Video Vanguard Award during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna (C) performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Singer Rihanna performs at the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson TPX IMAGES OF THE DAY

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna performs during the 2016 MTV Video Music Awards in New York, U.S., August 28, 2016. REUTERS/Lucas Jackson

Rihanna bows after performing "Love On The Brain" at the 2016 Billboard Awards in Las Vegas, Nevada, U.S., May 22, 2016. REUTERS/Mario Anzuoni TPX IMAGES OF THE DAY

Rihanna (R) accepts the Billboard Chart Achievement Award from presenter Idina Menzel at the 2016 Billboard Awards in Las Vegas, Nevada, U.S., May 22, 2016. REUTERS/Mario Anzuoni

Rihanna bows after performing "Love On The Brain" at the 2016 Billboard Awards in Las Vegas, Nevada, U.S., May 22, 2016. REUTERS/Mario Anzuoni TPX IMAGES OF THE DAY

Rihanna accepts the Billboard Chart Achievement Award at the 2016 Billboard Awards in Las Vegas, Nevada, U.S., May 22, 2016. REUTERS/Mario Anzuoni

Rihanna accepts the Billboard Chart Achievement Award at the 2016 Billboard Awards in Las Vegas, Nevada, U.S., May 22, 2016. REUTERS/Mario Anzuoni