

Attention could be drawn to its unique conjunction of musical styles, Green's startling vocal performance, its brutally spare construction and the duo's attention-grabbing habit of dressing up in Star Wars costumes or Clockwork Orange garb or nappies, without really getting to the bottom of what made it so spellbinding. There was something indefinable about Crazy's appeal. The accompanying album, St Elsewhere, was haunting and eclectic: it sold a million copies in the US alone, while making it clear there was no more where that came from. It won awards and endured more grisly cover versions than any recent chart hit, amazingly surviving the ministrations not just of a duetting Nelly Furtado and Charlotte Church, but Paris Hilton, the Kooks and ghastly operatic man-band G4 with its credibility intact. In Britain it was deleted while still at the top of the charts: it had been there nine weeks. Gnarls Barkley's The Odd Couple arrives two years after Crazy, a song that did substantially better business than an eerie mediation on mental illness had any right to.

W hat do you do when your debut single achieves a kind of unprecedented, global success that you know you can never repeat? That question looms over the second collaborative album by producer Brian "Danger Mouse" Burton and vocalist Thomas Callaway, better known as Cee-Lo Green.
