At the close of her recording career, Hills returned to England and film, appearing in Michelangelo Antonioni's first English language film "Blowup" (1966), starring David Hemmings, with whom her character and that of Jane Birkin shared an energetic romp. "Blowup" won the Grand Prix at 1967 Cannes Film Festival. Next came a play by David Storey at The Royal Court Theatre, "The Restoration of Arnold Middleton", director Robert Kidd, followed by the film version of John Osborne's play "Inadmissible Evidence" (1968), directed by Tony Page, in which she plays the part of Joy. Hills appears in writer James Salter’s only film as a director, a mystery romance "Three" (1969). Hills also starred as Alison in "The Owl Service" (1969), a television adaptation of the Alan Garner novel. 1970, Georges Franju chose her to play the part of Albine opposite Francis Huster in "La Faute de l'abbé Mouret", adapted from a novel by Émile Zola. Other film appearances followed, including a cameo in Stanley Kubrick’s "A Clockwork Orange" (1971), in which Hills played one of two girls picked up in a record shop by Alex (Malcolm McDowell). She replaced Marianne Faithfull in the 1972 horror "Demons of the Mind" for Hammer Film Productions.