If you only know him as the singer of "The Banana Boat Song," or know him for his Emmy and Tony-winning entertainment projects, you don't have a full picture of who Harry Belafonte is.
The singer's activism and humanitarian work are at the center of "Sing Your Song," which also touches on his long musical career.
Belafonte has played a role in nearly every political and social movement since his days as a supporter of the Civil Rights Movement and as a confidant of Martin Luther King Jr. He campaigned for John F. Kennedy, helped organize the March on Washington in 1963 and the "We Are the World" recording session in 1985, and has been an active fundraiser in efforts to help fight AIDS in Africa and children in genocide-stricken Rwanda.
King, JFK, Nelson Mandela, Sidney Poitier and Marlon Brando are among those who inspired Belafonte (and were inspired by him), and the title of the documentary comes from something told to Belafonte by one of the biggest influences in his life.
Fellow actor and activist Paul Robeson advised him to use his celebrity as an actor and singer for something important.
"Get them to sing your song, and they’ll want to know who you are," Robeson said.
The documentary, which opened the 2011 Sundance Film Festival, doesn't sugarcoat Belafonte's less-successful personal relationships -- the actor himself talks about his two failed marriages and his inadequacies as a father.
But his family, as well as famous friends like Nelson Mandela, Desmond Tutu, Diahann Carroll, Whoopi Goldberg, Tommy Smothers and Quincy Jones, make strong arguments that Belafonte's commitment to righting social and political wrongs will ultimately outweigh any shortcomings in his private life.
"Sing Your Song" premieres tonight at 10/9c p.m. on HBO.