Russian tennis player Maria Sharapova poses at the premiere of "10,000 B.C." at the Grauman's Chinese theatre in Hollywood, California March 5, 2008. The movie opens in the U.S. on March 7. REUTERS/Mario Anzuoni

Maria Sharapova of Russia reacts during her women's semi-final match against Eugenie Bouchard of Canada at the French Open tennis tournament at the Roland Garros stadium in Paris June 5, 2014. REUTERS/Stephane Mahe

Maria Sharapova of Russia poses next to a Boxster Porsche car as she visits the Taste Festival at the Grand Palais in Paris, France, May 21, 2015. Sharapova will compete in the French Open tennis tournament which starts on May 19th at the Roland Garros stadium. REUTERS/Charles Platiau - RTX1E4A6

Russia's Maria Sharapova sits in the shade of an umbrella during a break in her match against Italy's Flavia Pennetta at the Wimbledon tennis championships in London July 3, 2006. REUTERS/Alessia Pierdomenico

Maria Sharapova of Russia wears shoes with her name monogrammed on the back during the final of the Sony Ericsson Open tennis tournament in Key Biscayne, Florida, April 2, 2011. REUTERS/Hans Deryk

Maria Sharapova of Russia reacts after winning a point against Maria Elena Camerin of Italy during their match at the Nasdaq-100 Open tennis tournament in Key Biscayne, Florida March 26, 2006. REUTERS/Carlos Barria - RTR17N04

Maria Sharapova of Russia reacts during her match against Coco Vandeweghe of the U.S.A. at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY - RTX1JEK7

Russia's Maria Sharapova holds the women's U.S. Open trophy at the U.S. Open tennis tournament in New York, September 9, 2006.

Maria Sharapova of Russia holds a bag of her gummy candy line "Sugarpova" during a media availability at the BNP Paribas Open WTA tennis tournament in Indian Wells, California, March 6, 2013. REUTERS/Danny Moloshok

Russia's Maria Sharapova watches Bulgaria's Grigor Dimitrov play Israel's Dudi Sela in their men's singles tennis match at the Queen's Club Championships in west London June 10, 2013. REUTERS/Toby Melville

Russia's Maria Sharapova leaves a Pan Pacific Open Tennis Tournament news conference in Tokyo January 29, 2007. REUTERS/Toru Hanai

Tennis player Maria Sharapova of Russia plays with a fan during an event promoting tennis in Hong Kong, December 29, 2002. Sharapova, 15, the latest young player to be saddled with the title "the next Anna Kournikova", will participate in the Hong Kong Ladies Challenge which will begin on January 1, 2003. REUTERS/Kin Cheung BY,DL - RTR112FH

Russia's Maria Sharapova serves during her third round match against Lauren Davis of the U.S. at the Australian Open tennis tournament at Melbourne Park, Australia, January 22, 2016. REUTERS/Thomas Peter TPX IMAGES OF THE DAY - RTX23GW1

Tennis player Maria Sharapova (L) of Russia and NBA basketball player LeBron James of the U.S. pose for photographer Patrick Demarchelier (not pictured) for a United Nations Development Programme campaign in New York September 25, 2007. REUTERS/Joshua Lott

Maria Sharapova of Russia poses with her trophy and the Russian flag after defeating Caroline Wozniacki of Denmark in the women's singles final match at the BNP Paribas Open WTA tennis tournament in Indian Wells, California March 17, 2013. REUTERS/Danny Moloshok

Tennis player Maria Sharapova poses for photographers as she promotes her "Sugarpova" confectionary brand in London June 20, 2013. REUTERS/Neil Hall

Russia's tennis star Maria Sharapova (C) looks at two male models, who will act as ball-boys in the WTA Tour Championships in November during a selection process along with a celebrity panel, in a central hotel in Madrid May 11, 2006. REUTERS/Andrea Comas - RTR1DA5C

Vogue editor Anna Wintour (C) sits with tennis player Maria Sharapova (R) and singer Alicia Keys before a presentation of the Jason Wu Spring/Summer 2014 collection during New York Fashion Week September 6, 2013. REUTERS/Lucas Jackson

(L-R) Photographer Mario Testino, U.S. Vogue editor Anna Wintour and tennis woman Russia's Maria Sharapova attend the Spring/Summer 2016 women's ready-to-wear collection for fashion house Chanel at the Grand Palais which is transformed into a Chanel airport during the Fashion Week in Paris, France, October 6, 2015. REUTERS/Charles Platiau - RTS386T

Russia's Maria Sharapova sits on a motorcycle after defeating compatriot Vera Zvonareva in the final of the Qatar Open tennis tournament in Doha February 24,2008. REUTERS/Fadi Al-Assaad