In Immortals, opening today, he plays an overlooked peasant propelled to lead an army into battle against a sadistic king. But before Cavill could even step into the role's leather sandals, the untested actor had to convince director Tarsem Singh that he, too, had the right stuff.  Going into their first meeting, "I was an unknown. But I wanted it badly," Cavill says. "Tarsem saw the passion. And if you've got nothing else, passion will get you through."  The British actor, 28, has a lot more than passion going for him. His well-defined cheekbones and acting chops have made characters such as Charles Brandon on Showtime's The Tudors fan favorites. But after landing the part of Theseus in Immortals, he's out to prove he can carry high-profile projects, including the role of Superman in the highly anticipated Man of Steel (due in theaters in 2013).  "Things are pretty crazy right now," he says. "And I'm loving it."  Cavill has been on the verge of a breakout before. He had been in serious running for the role of James Bond but lost out to Daniel Craig ("I'll take that silver any day of the week," he says). And he says he was a near shoo-in for 2006's Superman Returns until a switch of directors pushed the part to Brandon Routh. Cavill just kept pressing on.  "In this business, 99% of the time you hear 'no,' " he says. "You have to put your head down and just deal. But when you do hear the response you want, it's a wonderful thing."  For Immortals, Singh had to persuade the studio to take a chance on the up-and-coming actor for the lead in the $75 million epic.  "They knew this was such a big film and I could go with one of the big actors, so why was I stuck on this unknown?" Singh says. "But I wouldn't come off the pole. They finally gave up and said, 'Have your guy.' "  There was one issue he had with his star, though.  "He was a little pudgy," Singh says. "I told him to get in shape while I got the script ready. I needed a swimmer's physique that was really trim. I needed an eight-pack."  The 6-foot-1 actor, who had earned the nickname "Fat Cavill" in his school days, started a strict diet and began a cardiovascular-heavy training regimen at 4 each morning before shooting the final Tudors season. He sent video proof of his improved body along the way. The results were clear.  "The body got harder and leaner," says Cavill. "But the biggest change was the waist getting smaller. A lot smaller."  On the Montreal set of Immortals, he trained with a core group of stuntmen for three months of warrior boot camp to perfect the intricate battle scenes. Together the army stayed fit by eating carefully portioned meals.  But there were the odd nights of levity at the local bar where Cavill wasn't exactly calorie-counting.  "When you train with guys and you're all eating nothing in order to be lean, there are those weekends," Cavill says. "There's no point in going halfway. You're going to wake up with a terrible hangover and think, 'OK, thank God, I got that out of my system.' "  On-screen, the film's climactic action sequence involves a hand-to-hand showdown between Cavill's Theseus and Mickey Rourke's King Hyperion. Though Cavill found the bad boy "quite sweet" in real life, their final fight scene was brutal, on-screen and off.  "It was basically two days of me getting beat up," Cavill says. "It was intense, but we got the final result."  He appeals to both sexes  The public will be the final judge of Immortals' box-office success. Chuck Walton, editor in chief of the movie ticketing website Fandango.com, believes Cavill will prove to be a major draw.  "Is it a gamble to put $75 million on an untested movie star? Yes. But Cavill proves up to the task," Walton says. "His 'it' factor is that he appeals to women and men. He's an old-school Hollywood type of star."  The big question will be whether audiences will head to Immortals as they did for similar-themed hits such as 2006's 300 (made by the same producers) or 2010's Clash of the Titans. But more recently, summer's Conan the Barbarian flopped, which could spell sword fatigue.  "Regardless of the financial take, Cavill shows he is a hero worth cheering for," Walton says. "Even if the movie ends up being a warm-up to Man of Steel, it shows the red boots and cape will fit this guy just fine."  The spotlight on Cavill only intensified after he was announced as the next caped superhero while Immortals was shooting in Vancouver. "When I cast Henry as an unknown, I was considered the fool," Singh says. "Eight months ago he's suddenly cast as Superman, and I'm the genius."  The Superman role has had an equally large effect on Cavill's body. Cavill had let the Immortals body slide while playing a regular-guy character in The Cold Light of Day. ("I did it through pizza and burgers," he says. "I didn't even look at a scale.") So when the call came from director Zack Snyder for Superman, he began weight-heavy training. The new body definitely has the bulk worthy of a superhero, even more dramatically than his Theseus body.  "I genuinely had to throw my clothes out, since my shoulders are too big and my waist is too small. Everything just doesn't fit like it used to. I have never been this big."  The metamorphosis staggered Immortals co-star Freida Pinto, who acknowledges that she had initial reservations about Cavill as the comic-book icon.  "I didn't see it on set, I have to be honest," Pinto says. "That might be because he was covered in muck all day (as Theseus). But now that he's all cleaned up, I look at him and see a fantastic Superman."  Sipping an early-morning cup of coffee on the rooftop of a Los Angeles hotel while scanning an aeriel view of Hollywood, Cavill does appear the very image of Superman, right down to the steel-blue eyes and the perfectly coiffed hair. He needs "a little product help" for the hair. ("I'm not going to lie," he says.) But the body that will fill the famous suit will be all his.  "This," he says, gesturing to his chest, "takes hours. It's been two hours a day for the last eight months."  The only thing not straight out of the famous comic book is the facial hair.  "The stubble is necessary," he says mysteriously, gesturing to his chin. "I have various stages of a beard (in the film)."  Superman with a beard? Cavill refuses to say more. It's part of the Superman secret. But now that Cavill is no longer a secret, he's enjoying some big Hollywood perks. Just flying to L.A. from the Man of Steel set in Vancouver was an adventure.  "I flew down here on a private jet, for goodness' sake," he says. "I was sitting there with sushi from the best restaurant in Vancouver in these leather seats.  "I was thinking that this is just amazing. Those are the best moments."
Henry Cavill morphs from "pudgy" Charles Brandon on 'The Tudors' to lean Theseus in 'Immortals' to ripped Superman in 'Man of Steel.'