Director Todd Phillips is following up his hit movie The Hangover with another comedy, Due Date, which tells the story of a father-to-be (Robert Downey Jr.) who reluctantly hitches a ride with a college slacker (Zach Galifianakis) in an attempt to get home before the birth of his child.
Alan Arkin told Collider that he has joined the production to play Downey Jr.'s estranged father, who Downey Jr. has not seen in twenty-five years. Arkin claims that his scenes are largely improvised.
We did a lot of improvising and restructuring the stuff I was in. [Downey Jr.]'s got a very, very fast mind. He thinks about every aspect of the production. He knows exactly what he needs and what the scene needs, and he's very quick to be able to play around with the structure, within all those things that are going on. He's a very, very smart young man.