Tracey Ullman is getting down and dirty with openly gay camp auteur John Waters. The Emmy-winning Tracey Takes On... star has signed as the lead in Waters's upcoming A Dirty Shame, with singer-actor Chris Isaak also set to join the cast. Johnny Knoxville, Selma Blair, and Paul Giamatti are already attached to the project, about a working-class convenience store owner (Ullman) who suffers a concussion only to become a sex addict with wild urges. Isaak will play her husband, who is trying to restore order with his wife and daughter. The project is due to start shooting later this year in Baltimore. Sources said either New Line Cinema or its specialty arm, Fine Line Features, will be the likely distributor.