Iñárritu Comedy Birdman Adds Edward Norton

NEW YORK - SEPTEMBER 20: Actor and UN Goodwill Ambassador Ed Norton attends the United Nations MDG Summit kick off at American Museum of Natural History on September 20, 2010 in New York City. (Photo by Joe Corrigan/Getty Images) *** Local Caption *** Ed Norton Photo: Joe Corrigan/2010 Getty Images

Birdman, the impressively starry film about Cash Money Records CEO Bryan "Birdman" Williams about Michael Keaton, Emma Stone, Naomi Watts and Zach Galifianakis all being in a movie together, has brought Edward Norton aboard. He'll play a bigheaded actor toplining a theatrical production based on a famous superhero role Keaton's movie star character pioneered. The dark comedy will come from Alejandro González Iñárritu (21 GramsBiutiful).