Heath Ledger and Jake Gyllenhaal put their careers on the line -- The young actors play cowboys in love in ''Brokeback Mountain''

Heath Ledger has recently learned that there is no better defense against the buzzkill of reality than a hit of 100-proof love. He was clearly drunk on the stuff this morning, when he emerged from his Brooklyn town house looking like he’d gotten dressed in the dark: gray pinstripe pants, two-tone wingtip boots, a red-and-white-striped French sailor’s shirt, and a long red stocking cap with a knot at one end, fashioned out of the sleeve of an old cotton sweater. He takes the sidewalk two squares at a time and grins as if he’s listening to beautiful music only he can hear. This is a gray fall day on the industrial edges of Brooklyn, but to Ledger, it may as well be springtime in Paris. Who can blame him? He took the biggest professional risk of his career and came out of the experience with a soul mate (actress Michelle Williams) and a new baby. It’s been two weeks since his daughter, Matilda, arrived, and Ledger extols the virtues of fatherhood like a man reborn. ”I feel like I’ve left the ship without my space suit,” says the actor, who spent the past year trying to rebuild his career. ”Everything looks and feels different.”

In many respects, he’s right. Just one year ago, it would have been tough to fathom that Ledger would be a front-runner in this year’s Best Actor race or that his lightning-rod new movie, Brokeback Mountain, would have emerged as a leading dark-horse contender for Best Picture. But that’s just how things have shaped up for director Ang Lee’s adaptation of Annie Proulx’s award-winning New Yorker short story, which traces the ardor and anguish of two cowboys (played by Ledger and Jake Gyllenhaal) who are sent to wrangle sheep on a Wyoming mountainside in 1963 and end up wrangling each other. The story unfolds over two decades, during which they endure loveless marriages to long-suffering wives — Williams and Anne Hathaway — and bide their time between perilous trysts.

Brokeback Mountain is but one of the numerous fall movies revolving around gay characters. What makes it so potentially groundbreaking, though, is that it has become something of a cinematic oxymoron: an unapologetically sexual love story between two men with a real shot at breaking out of art houses and into the mainstream. A kind of Romeo and Romeo on horseback, this tale of star-crossed love has generated rapturous buzz ever since it snagged the top award at the Venice film festival and took the Toronto film festival by storm. While it’s not the first gay-themed Oscar hopeful (Philadelphia racked up a Best Actor award for Tom Hanks), Brokeback defies the familiar stereotypes of what it means to be gay on screen (no one has AIDS or an affinity for interior decorating) and doesn’t cheat when it comes to the love scenes.

They kiss. They have sex. They cuddle. Oh my! Not so long ago, it would have been considered career suicide for a major male movie star to get hot and heavy with a man on screen. And in this climate of cultural conservatism, when elections can hinge on the demonization of gay marriage, Brokeback represents a huge gamble for everyone involved. Lee came to the project having cashed in some of his clout after his last project, The Hulk, failed to connect with critics or audiences. And nobody has more on the line than Ledger and Gyllenhaal, who risk alienating a huge portion of their core fan base — young men — by being perceived as soft or, as Ahnuld might say, girlymen.