Or maybe it just comes naturally. Whichever, Jake is breaking out this year due primarily to two demanding and controversial movies, Ang Lee's gay romance, "Brokeback Mountain," and Sam Mendes' nihilistic Gulf War drama, "Jarhead." "What's the world without controversy?" says the actor, 25, who just a few years ago was playing jailbait for older women in the likes of "The Good Girl" and "Lovely & Amazing."

"I would not want to be in a movie that didn't stir up people's opinions. The only problem I have is when people make opinions before they've seen something. Judgment before experience is something that is a fault of mine and a fault of a lot of people that I know, and I do not think it's a good thing in myself.

"When people see these movies, they'll see what they're about. But yeah, after they see them, they may have opinions."

Indeed, when "Jarhead" came out, complaints ranged from it being too negative a comment on our military to it not taking a stand at all regarding the current war in Iraq.

"Brokeback," nominated for seven Oscars, has kept its marketers awake nights worrying whether a serious physical and emotional relationship between two Wyoming cowboys, Gyllenhaal's Jack Twist and Heath Ledger's Ennis Del Mar, can find mainstream acceptance in a culture currently at extremes of unprecedented acceptance of and deep discomfort with homosexuality.

Gyllenhaal wasn't primarily interested in causing a stir, though. He just wanted to be in the best love story he'd read in a long time. "Brokeback" is based on an acclaimed short story by "The Shipping News" author Annie Proulx, and was adapted by Pulitzer Prize-winning Western novelist Larry McMurtry and his frequent collaborator Diana Ossana.

"Did it change my perspective on gay cowboys?" Gyllenhaal asks rhetorically as he wades into a barrage of rhetorical questions about the film's sexuality. "It's very hard to make this movie experience into a literal one. It's about the struggles of two people dealing with intimacy, to me. You don't have this ideal idea of love like you see in movies all the time. That thing like: It's supposed to happen between these two people, particularly a guy and a girl - and when he gets the girl at the end, the whole thing is all good.

"But this puts it in an environment where we've never seen it before. I think you walk out of this film feeling devastated in a lot of ways - but also feeling a real sense of benevolence."

Fine and dandy. But what most people are asking about is doing love scenes with Ledger.

"What I'm really interested in is why so many people are interested in how different it is," Gyllenhaal says with a hearty laugh. "And most of them are men! But I can't really tell you, except to say that it was an exfoliating experience, and one that I will do to service a film, maybe, but definitely not in my real life."

Exfoliating? Fair enough. But now answer the question.

"We didn't really rehearse it at all," the actor says with a more tentative chuckle. "We talked about it, I guess, a little bit. But on the day, there was a lot of choreography. It was a lot like whenever I'm doing a love scene with a woman in a movie. They have a particularly hard time not being objectified, so when you're working with them, it's always like, 'I'm gonna put my hand here, I'm gonna go here ...'

"It was very much the same thing. I think both Heath and I have worked with women in the past like that, so we worked with each other that way. ... It was like a dance, you know?"

Gyllenhaal actually gets more flustered when asked about the bisexual Jack's first romantic encounter with his future wife Lureen, played with evident gusto by all-grown-up "Princess Diaries" star Anne Hathaway.

"Oh, now it gets more complicated," he says, this time actually blushing. "It's easier for me to answer the questions about the scenes with Heath. Anne's a very beautiful girl, that's all I can say. Yeah, that's ... uh ... she's a very, very beautiful girl. She's ... very beautiful."

The actor can be similarly reticent about real-life relationships. After dating for a few years, Gyllenhaal and actress Kirsten Dunst reportedly broke up in the summer of 2004. Yet they've repeatedly been spotted together since.

"It's something that I even hate to talk about, because nobody really understands what goes on between two people, anyway," Dunst told U in the fall of 2004.

"I don't think anybody understands what anybody's relationship is, except for the people who are in the relationship," Gyllenhaal responds when asked to clarify.

On most other topics, Gyllenhaal is forthcoming to an almost aggressive degree. Take a recent report that he got a little too aggressive in an emotion-charged scene during "Jarhead," during which he chipped a tooth and came to actual blows with another actor.

"I love Jake's performance," says Anthony Swofford, the third-generation Marine who wrote the book the movie is based on and who Gyllenhaal plays. "It's thoughtful, introspective, rough, brash, conflicted ... and those are things that I was."

So, is there a dark, angry side to the usually sweet and sunny Gyllenhaal?

"I don't know," he muses. "If you don't know it yet, you'll know it soon. Hopefully,I'll play roles where all that stuff comes out. Darkness is a pretty broad word. I don't know what that is. But there are many more sides than I've shown in films up to this point. I'm not done yet.

"I'm just not the type of person who can really hold it in," Gyllenhaal admits. "You ask any of my friends. Unless it's a very important secret or something they really need me to hold onto, I'm the first person to be, like, 'No, wait, I'm really feeling this, and I need you to know.' "

This was demonstrated when, after waiting many anxious weeks to learn if he was in the running for the "Jarhead" job, Gyllenhaal phoned director Mendes in the dead of night to make an impassioned pitch for himself.

"I did call Sam at 2 in the morning to tell him why I wanted the part and was right for it," Gyllenhaal confirms, with no apologies. "Some have said, well, not a lot of young people would have had opportunities like that. But to me, it's the family business. If my parents did something else, I would probably be doing that, too. It just so happens that this is a kind of adored profession. And I adore it, but it's no different to me - in an odd way, and I know that it's hard for other people to think that - than any other family business."

Stephen Gyllenhaal directs both quality television and independent films, two of which - "A Dangerous Woman" and "Homegrown" - his son has appeared in. Naomi Foner Gyllenhaal has scripted several of her husband's films as well as the widely praised "Running on Empty" and the current release "Bee Season."

As for Maggie, she played her brother's sister in the surreal, indie coming-of-age hit "Donnie Darko" and has her own resume of provocative films such as "Secretary," "Adaptation" and "Confessions of a Dangerous Mind." They were also in some of their father's films together, and Maggie's boyfriend, Peter Sarsgaard, co-starred in "Jarhead."

It all adds up to an unusually close actors' support network.

"When I'm doing a movie, I'll finish a take and think, 'What would Maggie think if she saw that choice? Would she think it was interesting?' " Gyllenhaal says. "And I feel the same way about Peter. In terms of acting, I kind of group the two of them in that same category. I wonder, if they saw that, would they buy it, or would they know that I was pushing it or whatever? That's what was cool about working with Peter. He knows all the B.S., and we learned a lot about each other that we hadn't known before."

Gyllenhaal is currently working with Robert Downey Jr. and Mark Ruffalo on the true-life police procedural "Zodiac." How controversial that will end up being remains to be seen, but its director, David Fincher, has certainly caused commotions with films such as "Fight Club" and "Se7en" in the past.

Whatever complaints may come, Gyllenhaal remains flat-out giddy about where his career is at right now.

"Oh, without a doubt," he says with his broadest grin of all. "I mean, come on - it's not so often that you get to work with Ang Lee, Sam Mendes, John Madden (whose 'Proof' Gyllenhaal also appeared in this fall) and David Fincher within a short period of time. It's an embarrassment of riches. I don't expect that things like this come very often. So I have every intention to enjoy it - the good and the bad, really."