Celebrities including Renée Zellweger, Richie Sambora and Tommy Lee have signed up for US photo app Csnaps, which lets fans make donations to good causes in exchange for 'star selfies'.

Bon Jovi guitarist Sambora is using his pictures to support musical scholarships for low income children via the charity Ovation, rocker Lee is backing animal rights organisation PETA, and Bridget Jones star Zellweger is supporting The ALS Association. Fans who want a 'star snap' can download the Csnaps app and then, after the pictures are taken, make a $3 charitable donation to retrieve their image.