John Legend and Corinne Bailey Rae performing at Live Earth London Concert held at Wembley Stadium. London, England - 07.07.07

Rae and Legend performed a cover of Marvin Gaye hit Mercy Mercy Me at the London leg of the climate change awareness-raising event.

However, they had little to time to rehearse the number.

Rae explains, "We were crammed together in this cubicle. There was nowhere else to go that was quiet enough. We didn't have a chance to rehearse before that so we just had to get on with it."

Source: WENN