Duff, who will no doubt shed her good girl image after this naughty role, plays the part of a "slutty" pop star in the John Cusack film, War, Inc.
Cusack handpicked the pretty star for the drama, which satirises war profiteers.
"She played a pop idol from central Asia. So, she was like a Hilary but not Hilary, because Hilary is so classy, but like a real, and I won't name names, but a real slutty pop star. ... Hilary is the opposite of that, of course. I think for her to play that, or to parody that, was really great," Cusack told MTV.