When Birdman won Best Picture at this year's Oscars, Sean Penn opened the envelope winced and said “who gave this son of a bitch his green card?” referring to Birdman's director Alejandro González Iñárritu
It was clearly a joke, even the director himself made fun of himself saying something like maybe next year the academy should have some immigrant category or something. So, it clearly seems to be something he jokes about with him.
