Kristen Stewart was spotted stripping down to her underwear before going skinny dipping with Juliette Binoche on the set of their new movie "Sils Maria."
The "Twilight" starlet will play "Valentin" in the film, which tells the story of an aging actress (Binoche) who returns to the theater for the revival of a play that made her famous, except that this time she plays opposite to the young role she once had.