HOLLYWOOD -- Given Sam Rockwell's wacky gallery of colourful screen characters, the prospect of him letting loose in a horror movie sounded right up the hyperactive actor's alley.

After all, here was the guy who managed to steal the spotlight away from Tom Hanks as The Green Mile's psychotic convict Wild Bill Wharton and, likewise, from Tim Allen, Sigourney Weaver and Tony Shalhoub as bumbling actor Guy Fleegman in the 1999 cult sci-fi comedy, Galaxy Quest.

And let's not forget about gonzo Gong Show host Chuck Barris in George Clooney's Confessions of a Dangerous Mind or space cowboy Zaphod Beeblebrox in The Hitchhiker's Guide to the Galaxy.

So when the director of Joshua came calling, guess what role he had in mind for the actor whose fearless performances often seem to defy the laws of gravity?

Try an affluent, New York hedge-fund manager who lives in a swank Upper West Side apartment with his wife (The Departed's Vera Farmiga) and two children.

Mind you, his titular nine-year-old son is one creepy kid with a disturbing agenda, but still, Sam Rockwell as a family man in an expensive suit and tie?

"For me that was a nice departure," says Rockwell, as he scratches the serious-looking moustache that now hangs, Yosemite Sam-style, across his upper lip. "I got to really play a sort of normal guy. But he's complicated. He's got a lot of stuff going on but it's not on the surface."

There was no doubt in director George Ratliff's mind that Rockwell was the right man for the job.

"We offered him something that people don't normally offer him," says Ratliff, who previously directed the documentary, Hell House. "It's a totally different role for Sam and it's also a more restrained performance than I think you've seen. But I knew Sam could do anything."

To prepare for the part, Rockwell soaked up plenty of on-the-job atmosphere by spending time with a real-life hedge-fund manager.

It certainly represented a very different environment from Rockwell's decidedly more bohemian upbringing.

The only child of two actors who divorced when he was five, Rockwell's formative years were spent living with his father just outside of San Francisco and spending summers in New York with his mother.

"I was sort of shy and a loner. Then I was an extrovert and then I was kind of shy again. I'd go back and forth," says Rockwell. Judging from his body of screen work, the extrovert clearly won out in the end.

So, we can't help but wonder if the facial hair has anything to do with his coming role in Frost/Nixon?

"No, this is just for me," insists Rockwell. "You wear so many costumes as an actor and sometimes you just want a costume for yourself. I'm bringing the 'stache back, man. It's an homage to Nick Nolte in North Dallas Forty, and to Burt Reynolds."

But he is growing out his hair for the '70s-era film, in which he'll play James Reston, Jr., the acclaimed writer and historian whose book, The Conviction of Richard Nixon: The Untold Story of the Frost/Nixon Interviews formed the basis of the Broadway play.

Frank Langella will be reprising his Tony award-winning portrayal of the disgraced U.S. president in the Ron Howard picture.

"It's a great piece because there are a lot of parallels to what's going on right now with Bush and Iraq," says Rockwell. "It's very Mr. Smith Goes to Washington. It has a very moral message."

Hmmm. Moral messages. Financial-whiz family man. Could Rockwell, at age 38, be ready to settle down into a less-hyper phase of his career?

Nah. He points out he's also signed on to star in Choke, based on the Chuck Palahniuk novel about a sex-addicted medical school drop-out-turned-con artist.

That sounds more like it.