Hilary Duff Joins Chevy Chase in "Stay Cool"

Hilary Duff has joined the cast of the new Polish brothers comedy "Stay Cool," which stars Winona Ryder, Mark Polish, Sean Astin, Chevy Chase and Jon Cryer.

The project, which shoots in July in Santa Clarita, California, is described as a "knowing-your-age comedy," centering on a successful author (Polish) who is forced to confront an unrequited high school crush (Ryder) when he returns home to deliver a commencement address to graduating seniors.

Duff will portray Shasta O'Neil, a sexy high school senior who flirts with the visiting author and invites him to the prom.

Duff, who broke through by becoming a tween superstar via her Disney TV series "Lizzie McGuire," has been slowly moving beyond that audience. She can be seen in the political satire "War, Inc." opposite John Cusack and has films "Safety Glass" and "Greta" in the can. Duff will be back in the studio to work on her fifth album this summer.