The cast for the upcoming DreamWorks film “Dreamgirls” is starting to take shape. Not only has pop diva Beyonc Knowles signed on for one of the film’s starring roles, according to Hollywood trade magazine Variety, but Oscar-winning actor. Jamie Foxx and chart-topper Usher have also joined the cast. Knowles will play Deena Jones, the leader of a trio of female soul singers called the Dreams, who cross over to the pop charts during the early 1960s. The film an adaptation of the Broadway musical, believed to be loosely based on the Diana Ross-led act the Supremes will be directed by Bill Condon, who also wrote the film’s screenplay. Condon was the scribe who brought the stage musical “Chicago” to the big screen.