1 / 10

Joe Louis and Frank Sinatra - Frank Sinatra and boxer Joe Louis were very close friends. After Louis had squandered his earnings, Sinatra helped get Joe Louis jobs and also paid for his medical bills and funeral. (Photos from left: Weegee - Arthur Fellig/International Center of Photography/Getty Images, WikiCommons)

2 / 10

Muhammad Ali and the Beatles - When Muhammad Ali was still Cassius Clay he met with the English group the Beatles, who were making their first trip to the U.S. After the meeting Clay defeated Liston and then became Muhammad Ali and the Beatles went on to be one of the biggest musical acts ever. (Photo: Keystone/Getty Images)

3 / 10

Muhammad Ali and Sam Cooke - Sam Cooke was a good friend of Muhammad Ali and Ali even gave Cooke a shout out after beating Sonny Liston. The two took pictures together, hung out together and even recorded their own duet. (Photos from left: EMPICS /Landov, Michael Ochs Archives/Getty Images)

4 / 10

Muhammad Ali and James Brown - Ali was also friends with the Godfather of Soul, James Brown. The two put together a concert in Africa that happened before Ali's legendary "Rumble in the Jungle" with George Foreman. (Photo: Robert Abbott Sengstacke/Getty Images)

5 / 10

Mike Tyson and Canibus - Mike Tyson joined rapper Canibus for his 1998 LL Cool J dis song, "Second Round K.O.," adding his unique vocals and appearing in the video. (Photos from left: Hayley Madden/ Redferns, Chris Hyde/Getty Images)

6 / 10

Mike Tyson and Tupac - Mike Tyson and Tupac were very close friends. Tupac would call Tyson in prison and even make custom rap songs for Tyson's fight. Tupac wound up being fatally shot after a Mike Tyson fight in 1996. (Photos from Left to Right: Alexander Hassenstein/Bongarts/Getty Images, Raymond Boyd/Michael Ochs Archives/Getty Images)

Photo By Photos from Left to Right: Alexander Hassenstein/Bongarts/Getty Images

7 / 10

50 Cent and Floyd Mayweather - 50 Cent and Floyd Mayweather are on-again, off-again friends. 50 has appeared with Floyd at many fights and the two have made videos together and even formed the Money Team together before parting ways. (Photo: REUTERS/Lucas Jackson /Landov)

8 / 10

Martin Lawrence and Tommy "Hitman" Hearns - Before Kevin squared of with Sugar Shane, another comedian, Martin Lawrence faced off with boxer Tommy "Hitman" Hearns on his hit comedy Martin. (Photos from left: Ethan Miller/Getty Images, Alberto E. Rodriguez/Getty Images)

9 / 10

Floyd Mayweather and Justin Bieber - Singer Justin Bieber joined boxer Floyd Mayweather Jr. for his 2012 fight against Miguel Cotto along with rappers 50 Cent and Lil Wayne. Photo: Al Bello/Getty Images)

10 / 10

Mike Tyson and The Hangover Cast - Former boxing champ Mike Tyson is no stranger to comedy. He appeared in both of the hilarious Hangover movies and even did a song-and-dance number in The Hangover Part II. (Photo: Kevin Winter/Getty Images)

Photo By Photo: Kevin Winter/Getty Images