Bradley Cooper let loose on the dance floor with a mystery gal in Cannes on Friday night. The actor joined his pal Leonardo DiCaprio at a Red Granite Pictures party, where Kanye West took the stage and performed an hour-long set for the star-studded crowd. Bradley, who's single since splitting from girlfriend Renée Zellweger, worked up a sweat while showing off his moves and enjoying the company of his new lady. This is Bradley's latest international vacation with pal Leo, after the duo spent a guys-only weekend in Mexico for their mutual friend Ryan Kavanaugh's bachelor party. Bradley's well-versed in prewedding misconduct, and his new movie The Hangover Part II features him, Justin Bartha, Zach Galifianakis, and Ed Helms behaving badly in Bangkok. The guys monkeyed around on the cover of Entertainment Weekly recently, and this week they're doing more press with Zach stopping by Conan tonight and Bradley expected on The Ellen DeGeneres Show tomorrow.