Playful, innocent and childlike: a hitherto unseen side of Kurt Cobain is captured by a new exhibition of photographs showing raw emotion off stage and Nirvana's exhilarating performances on it.

Familiar images and unpublished work by Ian Tilton, the first British photographer to shoot the band, and Charles Peterson, who documented the birth of the grunge scene and was one of the last people to see Cobain alive, will go on display at the Sony Ericsson Proud gallery in central London this month.

One of the Peterson pictures is a previously unpublished photograph of Cobain in Seattle the year before he died, with his wife Courtney Love and their daughter Frances Bean (right) while another is of Cobain in a wheelchair at the Reading Festival in 1991. Ian Tilton's images include Cobain pulling a face and crying.

More than 11 years after Cobain committed suicide aged 27, he and Nirvana continue to fascinate. Last Days, Gus Van Sant's fictional film of Cobain's final hours at his home in Seattle, has been a critical and commercial success.

Peterson thought Nirvana were terrible the first time he saw them play "but that changed and they started blowing everyone away". For Tilton, Cobain was enigmatic, but it is the portrayal of his angst, slumped on the floor and crying backstage, that has become rock iconography.

· Nirvana - With the Lights Out, Sony Ericsson Proud Central, 5 Buckingham Street, London, October 27 to November 20