Is Britney Spears planning a movie comeback? The pop tart turned up at a small screening of Abe Sylvia‘s “Dirty Girl” at William Morris’ offices in LA. The film, about a slutty Oklahoma teen in the ’80s, was acquired by the Weinstein Co. during its world premiere at the Toronto Film Festival. A spy reports a low-key Spears “came in five minutes after the movie started and left a few minutes before the movie ended.” Spears is repped by the agency and is staging a revival of sorts, having appeared in this week’s “Glee” episode.