He's hard to pin down—and that's exactly how Paul Bettany likes it. The lanky 38-year-old Brit, who made his cheeky Hollywood debut flashing his ass in A Knight's Tale in 2001, has since been a figment of the imagination (A Beautiful Mind), a sinister albino monk (The Da Vinci Code), and a 19th-century lord (The Young Victoria). So much for being typecast. "I get bored easily," he admits.

This month there's no chance of tedium, as two polar-opposite Bettany flicks premiere. In the apocalyptic Legion, Bettany—who stands at a heavenly 6'3"—plays the semiautomatic-toting Archangel Michael. His tough-guy look was enhanced by a set of ripped abs (just glance at his shirtless movie poster and you'll see what we mean). "I'm a European," Bettany laments of being denied beer, cheese, and bread while filming. "That was my entire diet!"

Luckily, the menu for Creation was pub-friendly: To transform into the paunchy Charles Darwin, Bettany gained a whopping 45 pounds. He didn't miss the gym. "Genetically speaking," he jokes, "I'm designed to sit on verandas and have drinks brought to me." In the film, Bettany's real-life wife of seven years, Jennifer Connelly, plays the ultrareligious Emma Darwin, who struggles with her husband's theory of evolution. Working with Connelly added an "easy intimacy" to their scenes. "In marriage," he teases, "there's a lot of ignoring each other, which is hard to fake on-screen."

Offscreen, he gushes about teaching his sons—stepson Kai, 12, and Stellan, 6—guitar on weekends spent in Vermont, away from their lower Manhattan loft. On naming their youngest, Bettany explains, "We did a survey, and women thought Stellan was a sexy name. He'll thank us at 15 when girls are swooning." Then he jokes, "Paul is an awful name. I might as well be Bob." Bob, Paul, who cares? We'd love him if his name were Sue.

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