LOS ANGELES — Fame hasn’t necessarily changed Dax Shepard, but the Punk’d and Without a Paddle star has noticed a large change in the ways that people describe him.

"I’m going through the cute factory that Jimmy Fallon did," the 30-year-old comic says. "All of a sudden everyone’s like, ’Yeah, he’s cute.’ And you’re like, ’Oh, really? When did that happen? Because he was just kinda a little guy before and now he’s cute? OK.’ "

Only barely removed from suckering celebrities with Ashton Kutcher and one year after he scored a hit cracking not-so-wise with Seth Green and Matthew Lillard, Shepard is taking advantage of the most unusual of career opportunities. With only a hint of humor, he’s playing Astronaut, the hero of Jon Favreau’s Zathura.

"Favreau called me," he says. "I didn’t know him and he said, ’I want you to play the astronaut in this movie I’m doing,’ and I was blown away that he knew who I was or had gotten my number. It was creepy and flattering."

Shepard’s lack of previously displayed dramatic chops isn’t an obstacle in Zathura. Acting opposite pint-sized co-stars Josh Hutcherson and Jonah Bobo, Shepard gets to zoom around on a jet-pack, battle aliens and occasionally save the day.

"I think that although I’m doing something different, I’m still giving you a bit of what I think the five fans I have do like about me," he says. "I’m a little bit rough around the edges, even as an astronaut."

He expects that Zathura is about as serious as viewers are likely to see him.

"Am I one of those comedians that has to prove to the world I’m a great actor? No, I don’t need to do that," he says. "It’s, in my opinion, harder to prove you’re a great comedian than to prove you’re a great dramatic actor. So I don’t have that hang-up, I think, that some people do. But I will do any work that is fun or exciting or challenging, including, [expletive] tilling your garden. I’m saying it. Yes. I will do it."