Worthington hasn't abandoned that populist tilt. "He's driven to personal excellence as he defines it," Cameron says, "not as everyone else defines it. He doesn't make the distinctions that other actors make, as in, 'I'll do this one for the money, then this little indie movie for the art.' Sam does them all for the art. That's a very distinct difference between him and other actors."

If that bohemian side isn't always apparent in his work, where his major roles haven't even involved bona fide human characters (man-robot in Terminator Salvation; man-alien in Avatar; man-god in Clash of the Titans), it's obvious in his lifestyle. "I can survive on nothing," he says, and in some sense, despite the millions he has collected since signing on to Avatar, he does. "He couldn't give a fuck about money," says McG. "He's homeless, or very nearly homeless—I don't think he has a place to hang his hat. He's got two bags. Books in one, clothes in the other." Meaning, he hasn't changed all that much since he auctioned everything off, then hunkered down on a working spree that's showing no signs of ebbing. Sure, he's traded the shitbox Camry for the well-appointed hotel rooms he drifts in and out of ("I like room service," he admits. "They put a chocolate on my pillow. It's kinda cool"), but it's still the same "gypsy existence," as Cameron calls it. Worthington doesn't even own a cell phone, preferring to skip from one phone the studios force on him during production to the next. And fame? Fuck it. If he'd wanted fame, he's said, he could've gone on Big Brother.

"Most people could say, 'I want to be on magazine covers. I want to have enough money to buy a house,'" he says. For Worthington, however, the goal isn't nearly so tangible. "If it was tangible," he says, "hopefully I wouldn't be doing it, to be honest."

"Sam is always overthinking everything," Saldana says. "He's sensitive to so many things that normal people take for granted. That beautiful quality is what keeps him up at night and what makes him restless." His core identity, according to McG, "comes from a hunger. He knows damn well what it's like not to have that phone ringing." And so he keeps working, working, seemingly immune to the pitfalls of fame and fortune ("If you start walking around in a red chinchilla, thinking you're better than everybody," Worthington says, "you're going to look like a dickhead"), by keeping a tight, rigid focus on the time between when a director yells "Action!" and when he yells "Cut!" Cameron, says Worthington, once marveled at his lack of interest in the long term. "'You're not even thinking about what the movie's going to do,'" he says the director told him. "'I give you a problem and you solve it, and we figure it out in a day.' And that's true. I like that. It's like being a grunt in the army."

That doesn't necessarily translate into blind obedience. Worthington is prickly and prone to fierce, sometimes shouted opinions. When Christian Bale, his Terminator Salvation costar, became an Internet sensation and a late-night punch line after audio of an infamous on-set rant was leaked, Worthington reportedly told Bale, "I'm waiting for my tirades to come out." "People like Sam will scare you at first," says Saldana, "because we're all so used to living in the gray. Sam is very black-and-white." By his own admission, he was fired from an Aussie soap opera for asking too many questions; when he was up for the role of James Bond that went to Daniel Craig, he reportedly told Casino Royale director Martin Campbell that Campbell's idea of Bond was all wrong, citing his own, darker interpretation of Ian Fleming's novels. (He's now the favorite to succeed Craig as the next 007.) "Well, I demand a lot," he says, then backtracks, not wanting to position himself as some kind of diva. "I demand excellence in myself. I'm up front and quite outspoken, but I'll give you everything."