Serious filmmaker Alejandro González Iñárritu (Babel, Amores Perros , 21 Grams) is getting ready to make his first comedy - albeit a dark one - and, according to The Hollywood Reporter, he’s cast Michael Keaton, Emma Stone, Naomi Watts, and Zach Galifianakis in prominent roles. The movie, called Birdman, follows an ex-actor who played an iconic superhero (Keaton) as he puts together a Broadway play based on a Raymond Carver story in an attempt to get his career back on track, only to have the play’s cocky lead actor muck things up. Stone plays Keaton’s newly-rehabbed daughter/assistant, Watts portrays an actress, and Galifianakis is a conniving producer. Casting ex-Batman Michael Keaton as a guy who once played an iconic superhero is pretty on the nose and should be fun to see. Alejandro González Iñárritu directing a comedy is surprising, but not as much so as yesterday’s news that Jon Stewart is taking a Daily Show hiatus to direct a geopolitical drama. It’s like Iñárritu and Stewart are part of some sort of genre exchange program.