If anybody knows the secret to how one acts when starring in big-screen, big-effects summer movie spectacles, it's Brendan Fraser. The guy's done two Mummy movies, with a third in theaters in August. And he's in "Journey to the Center of the Earth," a 3-D action epic, opening Friday.

"I have to believe what I'm playing against is real," says Fraser, who faces a T-Rex and gigantic Venus flytraps in "Journey." "If I don't, the audience will sense that, and the movie won't work."

So the director, Eric Brevig, has to be the one who gives Fraser's trade secret away.

"He'll slug down a couple of Red Bulls, one right after the other, before a big scene," Brevig says, laughing. "That's technique!"

Fraser, 39, has done his share of edgy, indie fare, turning in winning performances in films from "Gods & Monsters" to "The Quiet American" and "Crash." But his forte is lighter fare, and his niche seems to be big, family-oriented action-adventures. He loves the idea of making movies his kids (he has three) would love.

"You do something like this and you watch a kid of 8 sit through it and you know what unbridled glee looks like," Fraser says.

And if family film is his niche, his MO as an actor doesn't hurt. He's a nice guy. Everybody says so. "Approachable" reads his bio on the Internet Movie Database. Funny, too, a bit of a goof. He won the job in the break-out hit "George of the Jungle" by working out for months, then tearing off his shirt in the audition. He tries his hand at a James Mason impression when recalling the 1959 big screen version of "Journey to the Center of the Earth."

"Brendan's just an incredibly likable human being," offers his "Air I Breathe" screenwriter, Bob DeRosa. "Very charming and funny."

"He's fun to watch as a guy who can't seem to do anything right," says Brevig.

And "his 'big dumb guy/Dad' persona can carry a film," adds the movie biz Web site Fantasymoguls.com.

Which is why you can look forward to seeing him in "three gorgeous dimensions" in "Journey to the Center of the Earth," in August in "The Mummy: Tomb of the Dragon Emperor," and early next year in the fantasy "Inkheart," based on the Cornelia Funke novel, playing, yup, "a dad, who, little does his daughter realize, when he reads aloud can make things in the books become real."