'Monsters vs. Aliens' invades theaters everywhere Friday -- in 3-D at select theaters and IMAX -- and our own Kevin Frazier caught up with two of its stars, Kiefer Sutherland and Hugh Laurie, who found the animated movie process a refreshing detour from their well-known TV personas.

"Playing a cockroach is a different tone, and it's good fun to let rip," says "House" star Hugh. "There's a slight Vincent Price-ness to his character."

Hugh plays Dr. Cockroach Ph.D., a mad scientist whose unfortunate experiments fused him with the giant head of a cockroach (just like 'The Fly'), while Kiefer plays General W.R. Monger, the leader and caretaker of the hidden-away monsters who battle aliens from another world.

"I loved the sergeant in 'Full Metal Jacket' -- he's so demonstrative and he's just unrelenting," says "24" star Kiefer of his vocal approach to his character. "To counterbalance that for young people, so they weren't scared, was one of my favorite cartoon characters, which is Yosemite Sam. We started to blend the two voices together and kind of went off in that direction."

Asked who is smarter, House or Dr. Cockroach, Hugh muses, "The cockroach has got some game, there's no question, but I think House has got double game. But the cockroach improvised a computer out of a pizza box -- don't try that at home, kids. Okay, so maybe House couldn't [do that] -- we're butting up against the wall of reality, though, aren't we there?"

Ultimately, the film's whimsical mixture of physical comedy with classic monster and alien movie nostalgia is what hooked Kiefer.

"You have adults and children laughing at the very same time for very different reasons, and that's a really delicate thing to maneuver," he explains, "and I think the writers and the animators did a beautiful job with it."

'Monsters vs. Aliens' also stars the voices of Reese Witherspoon, Seth Rogen, Will Arnett, Rainn Wilson, Paul Rudd and Steve Colbert.

Watch ET for more with the stars of the movie!