Beyonce Knowles is set to star as soul icon Etta James in the new movie, Cadillac Records. Now according to the Hollywood Reporter, Mos Def, who is currently staring in Be Kind Rewind, is joining the cast and will play Chuck Berry. The rock & roll movie will feature a huge cast including Adrien Brody, Jeffrey Wright, Eamonn Walker, Gabrielle Union and Cedric the Entertainer. Darnell Martin, who also wrote the script, will direct Cadillac Records, which tells the story of the legendary Chess Records label. The movie is currently being filmed in New Jersey.