Sienna Miller the 25-year-old actress is starring in the movie “Hippie Hippie Shake”, playing a free-loving flower child alongside American-born actress Margo Stilley and Cillian Murphy.

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

The movie, to be released next year, is based on the hedonistic memoirs of the Australian journalist Richard Neville.