An interview with the subject of this year's Oscar-winning documentary, Searching for Sugar Man. Sixto Rodriguez was a 1970s folk singer who sank into obscurity in the US, only to find out 20 years later that in South Africa he was bigger than the Rolling Stones. Rodriguez and director Malik Bendjelloul tell Xan Brooks about a new documentary about the singer's incredible story. Searching for Sugar Man is released in the UK on Friday