Zach loves Robert Downey Jr's face
Robert Downey Jr's face is the funniest thing about forthcoming film Due Date, according to his co-star Zach Galifianakis.
Robert and Zach, who starred in The Hangover, hit the road as mismatched travelling companions in Due Date.
"To me, the funniest part about the movie is Robert's reactions to things," Zach said at the ShoWest convention in America.
"There's antics that I do, but any time you go to Robert's face, that to me is the real great thing about this," he added.
Todd Phillips, who directed the Hangover, has cast Robert as a first-time dad forced to hitch a ride with a wannabe actor (Zach) to make it home in time for the birth of his baby.
"I've never worked with anyone like ZG, because there's no telling what he might do," Robert said. "Just because you're on set doesn't mean that's where the scene's going to go, which to me is even a step beyond my own managed insanity. But it's not because he's not contained. He's just completely free."
"No one is really the straight man in this movie," added Downey, "but I am kind of like this stick that's pounded into the ground, that I think a lot of people can relate to."