EARLIER: Inarritu’s upcoming film “Birdman” acquires a cast that includes Keaton, Emma Stone, Zach Galifianakis and Naomi Watts. The director of “Biutiful,” “Babel,” and “21 Grams” is well used to dark, but this will be his first attempt at dark comedy. The movie is about a has-been actor, famous for playing a superhero, who now attempts to star in a Broadway play based on the Raymond Carver short story. Keaton, who starred as Batman in Tim Burton’s 1989 and 1992 films, will play the main character. Stone stars as Keaton’s character’s daughter, Watts will play an actress in the play, and Galifianakis stars as the producer. Production should start in April.