So You Want to Be in Pictures (1947)

Joe McDoakes (George O'Hanlon) decides he wants to be an actor. After a few at-home lessons--he come out speaking in a French accent like Charles Boyer--he heads off to the studio after arranging an interview with director Anthony Anguish. His first mistake is to walk onto the set while they are filming; and then his take on the role leads the director to walk off the set in despair. He finally gets a role, but it's not quite what he expected.