"He's the opposite of narcissistic," says James Cameron, who might be called Worthington's fairy godfather for plucking him from semi-obscurity and casting him, against mighty studio resistance, as the lead in Avatar, which would become the highest-grossing movie ever made. "He doesn't play the Hollywood game. He's not here to make friends." That helps explain the antipathy toward interviews. A onetime bricklayer, Worthington considers acting no more and no less than a job—"Get up in the morning, go to work, make the boss happy"—rather than a goo-gooey sacred calling. And talking about work, while ostensibly part of the job, isn't the same as working, which seems to be Sam Worthington's innermost and outermost desire: to be constantly, strenuously working.

"He's a machine," says his Avatar costar Zoë Saldana, but a machine without an apparent off switch. This month he stars in Clash of the Titans, another 3-D epic, this one of the swords-and-sandals variety—Worthington plays the Greek hero Perseus alongside Liam Neeson and Ralph Fiennes. Two of his other movies slated for this spring—Last Night, a romantic drama with Keira Knightley and Eva Mendes, and The Debt, in which Worthington costars with Helen Mirren—have had their releases put on hold by the collapse of Miramax Films. But he was on the headlong pace to have five movies—counting Avatar and last summer's Terminator Salvation—come out in a 12-month span. "I hate downtime," Worthington says, casting a glance at the photo assistants and handler types who are enjoying their pre-shoot break by playing a sloppy game of Ping-Pong in the green room. "This is the first time I've had time off. I hate it." Clearly this is not a man resting on his laurels, or on anything else.

To understand that restlessness, however, is to begin to understand Sam Worthington—or at least the Sam Worthington who emerged from his man-in-the-mirror moment and subsequent life-liquidation sale. There's a before and an after in Sam Worthington's life, going something like this. Before: His boyhood, near Perth in Western Australia, was a standard-issue Aussie one—rough-and-tumble, outdoorsy, bookmarked by soccer and surfing. "I'm not a great fan of people who say they put a sheet up in the backyard when they were 7 and entertained all the neighbors," he says. "When I was 7, I thought I was a fucking fire truck." No youth theater, in other words. Not even a puppet show. "Growing up, you tended to just go through school to get out," he says, "then figure out what you want to do in this big ball of mud."

When Worthington was 17, his father, a power-plant worker, gave him a hundred bucks; a one-way ticket to Cairns, on the country's opposite coast; and the instruction to "work your way back." Worthington drifted down to Sydney, found a job laying bricks. "My mates were laborers, their dads were laborers, so you do that to get your pocket money," he says. Two years later, a dreadlocked Worthington tagged along with a girlfriend, an aspiring actress, to her audition at the National Institute of Dramatic Art. For "moral support," he says, he auditioned alongside her. He got in; she didn't—and promptly dumped him.