If it weren’t for his flat delivery and straight-face, actor Colin Hanks would seem to suffer from the kind of hyperbole-laced rhetoric usually reserved for fresh-faced ingénues.

Asked about his current Broadway debut in “33 Variations,” he responds: “It’s extremely exhilarating to get the chance to do this with someone like [playwright] Moises [Kaufman], who is extremely talented and an incredible human being and individual. It’s humbling and amazing and I’m very lucky to be here.”

This story first appeared in the March 5, 2009 issue of WWD. Subscribe Today.

What’s it like working with Jane Fonda?

“She’s extremely sweet and very hard working and just an absolute pleasure to work with.”

And John Malkovich, with whom he appears in the forthcoming film “The Great Buck Howard”?

“He’s just one of the sweetest individuals I’ve ever met. And extremely funny. I had a very good time working with him.”

Hanks, 31, can be forgiven a little gushing when it comes to such heavy-hitting co-stars, though with his Hollywood pedigree (yes, he’s Tom’s son) he’s certainly accustomed to Oscar-worthy company. And if his earnest manner doesn’t exactly make for zingy one-liners, it’s allowed him to maintain a steady stream of work.

In “33 Variations,” opening Monday at the Eugene O’Neill Theater, Hanks plays a male nurse charged with the care of Jane Fonda, an ALS patient and musicologist obsessed with Beethoven’s “Diabelli Variations.” She butts heads with her daughter (Samantha Mathis), who ends up finding romantic solace with Hanks.

“His character has a tendency to sort of fumble his words sometimes, and you’ll see there are some really funny moments in the play where he just makes absolute faux pas and things don’t quite come out way he means them to,” says Mathis. “It’s very charming.”

Though it is Hanks’ first professional theater role since a successful London run of “This is Our Youth” in 2003, he has plenty of academic stage experience. Growing up in California, he acted in all of his high school plays “with the exception of the musicals….I have crampy jazz hands,” and studied drama at Los Angeles’ Loyola Marymount University. His big-screen breakout came in the 2002 comedy “Orange County” and he has since appeared in “The House Bunny,” “Untraceable” and was a recurring guest star on the most recent season of “Mad Men.”

“Acting was always something I really loved doing. I wanted to make sure that there wasn’t anything else I wanted to do more,” explains Hanks, who now lives with his girlfriend in the West Village. “Then after going to school, I said, ‘Yeah, this is what I really love and what I want to do.’ I know there’s gonna be X amount of things that are always gonna come up, no matter what.”

Indeed that “X factor” — aka Dad — comes up in his latest film, “The Great Buck Howard,” out March 20. Hanks is Troy, a law school dropout who takes a gig as the personal assistant to washed-up mentalist Buck Howard (Malkovich). In a bit of art imitating life, his onscreen father — none too pleased about his son’s scholastic abandonment — is played by the elder Hanks (whose company, Playtone, also produced the project).

“I’ll be totally honest: That was his idea,” says the young Hanks. “He just sort of said, ‘Hey, I’m gonna do this — I hope you’re cool with it.’ And I thought, ‘OK, well, I mean, he’s good and he’s a talented guy and it wouldn’t hurt having him in the movie. I suppose yeah, OK, sure.’”