premise: Warren Beatty worked with Trevor Griffiths.
hypothesis: Shampoo is a 1975 American satirical romantic comedy-drama film written by Robert Towne and Warren Beatty and directed by Hal Ashby . It stars Warren Beatty , Julie Christie and Goldie Hawn , with Lee Grant , Jack Warden , Tony Bill and in an early film appearance , Carrie Fisher . Warren Beatty . Beatty is the first and only person to have been twice nominated for acting in , directing , writing , and producing the same film -- first with Heaven Can Wait ( 1978 ) , which was co-written by Elaine May and co-directed by Buck Henry , and again with Reds , which he co-wrote with Trevor Griffiths .