Sienna Miller is starring in the movie Hippie Hippie Shake, playing a free-loving flower child in the swinging sixties alongside Margo Stilley and Cillian Murphy.

With filming already under way, Miller has had to grow her hair long and dye it from blonde to brunette. It is understood directors have also asked Miller to cut down on her exercise regime to develop a more rounded physique, in keeping with the less gym-honed women of the era.

Sienna Miller on the set of Hippie Hippie Shake (NSFW)

photo source: Egotastic!