Susanne Rostock has long worked as an editor on American political and society documentaries, including a number directed by Michael Apted, and Sing Your Song, which she both directed and edited, is a skilfully compiled celebratory biography of Harry Belafonte. He was born into poverty in Harlem in 1927, raised in his father's native Jamaica, and after serving at sea in the US navy at the end of the second world war, he worked as a janitor before being drawn into the theatre. From the late 1940s on he was primarily a singer, becoming sensationally successful in the 1950s as the "King of Calypso". Sadly he has made only a handful of films, three of them minor classics – Carmen Jones, Odds Against Tomorrow and Kansas City, a role that Robert Altman had to talk him into playing.

This excellent film, eloquently narrated by its octogenarian subject in that wonderfully husky voice, carefully balances an account of his career in showbusiness with his 50-year commitment to civil and human rights in America and around the world, not just for fellow African-Americans but for Native Americans, Hispanics and people throughout Africa. The two aspects are of course closely interwoven, for he has courageously used his popularity and his charismatic presence to challenge the colour bar in the media, to attract attention to causes he believes in and to recruit his fellow performers to lend their support. The film's title, which reflects the way his life is integrated, comes from a piece of advice his hero Paul Robeson gave the young Belafonte when he dropped in at a folk music club where Harry was performing. "Get them to sing your song," Robeson said, "and they'll want to know who you are." For the most part Belafonte appears to use his power and influence wisely and well, and he emerges at the end as a man of bravery and probity, a formidable contributor and witness to his times.