Director Alejandro González Iñárritu has knack for attracting impressive names to his movies and his upcoming 'Birdman' is no exception. Emma Stone, Michael Keaton, Naomi Watts and Zach Galifianakis have all joined the project, which sounds like an interesting left turn for a filmmaker usually known for his pitch black dramas.

Unlike Iñárritu's previous films (which include 'Amores Perros,' '21 Grams' and 'Babel'), 'Birdman' is a comedy, but we suspect it will have plenty of his patented pessimism and disdain for happy moments. The Hollywood Reporter says that the film "...follows a former actor, who once played an iconic superhero, as he mounts a Broadway play based on a Raymond Carver short story in a bid to reclaim past glory. However, the play’s egotistical leading man threatens to throw everything down the tubes."

In an amusing bit of casting, former Batman Michael Keaton will play the role of the former superhero actor. Emma Stone will play his daughter and assistant, newly released from rehab. Naomi Watts will play a lead actress in the play. Zack Galifiankis will play a "conniving" producer. That's a murderer's row of talented folks, particularly for a comedy.

Of course, the key to a successful comedy is whether or not we end up laughing. Casting people as naturally hilarious as Keaton, Stone and Galifiankis is an incredible start (the jury's still our on whether or not Watts can be funny), but we'll have to see if Iñárritu can either rein in his natural glumness or find a way to transform it into humor. This will be an interesting project to say the very least.

'Birdman' should begin filming in April for a 2014 release.