Robert Downey Jr. and Zach Galifianakis team up for the road-trip-from-hell comedy 'Due Date,' and the quirky pair reveal their own twisted road trip tales to ET's Samantha Harris. Plus, watch the video for their reaction to Charlie Sheen's recent tabloid tangle, in which Robert calls the "Two and a Half Men" star a "genius"!
"Road trips, I've been on many, mostly on Greyhound," says Zach. "You know, they have the mile-high club, like on a plane, it's the same thing on a Greyhound. It's called the three-foot-high club. … It's not as romantic, especially if it's with the bus driver."
"I went cross-country a couple times -- with my dad, by the way, speaking of the dad theme. Brought us closer together," says Robert. Responding to whether or not he and his father had any arguments in the car, he jokes, "I don't necessarily remember, but he would put me to bed with chloroform. I mean, hot milk, to me, just wasn't cutting it."
'Due Date,' in theaters November 5, follows Robert as a soon-to-be first-time dad who is so desperate to get home to his wife, who is due with their baby in five days, that he hitches a ride with a wannabe actor (Galifianakis) after they're kicked off their flight. The ultimate road trip from hell ensues…
"It's not a message movie, but it's not just some ribald comedy. It actually has some emotional depth to it," explains Robert.
Zach sports a perm in the movie, and his amused co-star informs him, "Can I tell you I miss the perm? Ah, it was so great, dude. Particularly when it would start relaxing too much and it was just almost kind of like Tito Jackson ringlets."
"When you wet it, it smells like a Sally Beauty Supply store, like it's got that chemical thing, which is gross," says Zach. "Yeah, I do not miss the perm at all."
Watch ET for more with the stars of 'Due Date'!