St. Trinian's (2007)

Set in an all-girls school on the verge of bankruptcy, the UK comedy St. Trinian's (2007) stars Talulah Riley, Gemma Arterton, Antonia Bernath, and a host of British starlets as a group of rowdy teenagers who have to find a way to keep their beloved school open.

Colin Firth gives his grand glutes to the world, standing back turned, to the camera in the end credits.  Some folks think this might be his first and only nude appearance, but he also got nude in "A Single Man".  We think it might be the Firth, but definitely not he la-th.