Nicolaj Coster-Waldau has come a long way to become the finest sword in all of Westeros, playing Jaime Lannister in the HBO medieval fantasy series Game of Thrones and gracing the cover of the May issue of Men's Health.

Off-screen he speaks with the slightest of accents ("usually" comes out yew-shwelly), and he carries himself with a hint of old-world formality. Except for those clues, you wouldn’t suspect that he spent his childhood  in the village of Tybjerg, in Denmark, home to exactly 40 people.

A talented athlete, he had early dreams of glory on the fodbold field. Between schoolwork and practice, however, he was devising an even more audacious plan. "I always wanted to be an actor, but I just never told anyone," he laughs. "I had this superstition that if I said it out loud, it wouldn’t come true." (Make 2013 the year you hit your career goals with these 30 tips to soar ahead in the workplace.)

As a teenager, Coster-Waldau, now 42, recalls being entranced with the layered performances by the actors in the Sergio Leone gangster epic Once Upon a Time in America—still his favorite movie.

"Here I was growing up in a tiny village in Denmark," he says. "And I’m identifying 100 percent with this gangster from New York. And I think how amazing would it be to explore human behavior in that same way." (Is she into you? Or is she just acting? Find out what her body is telling you.)

He spent the next decade-plus, working his way up the acting food chain. And now he's tantalizingly close to the top.This year alone he shares screen time with Tom Cruise and Morgan Freeman in Oblivion, Jessica Chastain in Mama, and Juliette Binoche in A Thousand Times Good Night. The man keeps very good company.

Much of this success, he says, can be attributed to lessons learned in athletics. "I love team sports," he says, "and being in a movie [is like that]. If you’re not good, you’re going to pull everyone down."

And he has honed his own ability to perform in the moment. "You have to be sharp when the camera's rolling," he says. "I want to be totally unselfconscious, like a child playing. I do as much prep as possible so I can lose myself for those seconds." (Start pulling your own weight. Eight weeks on one of these 20 high-octane workout plans will set your gut aflame.) 

His loss has been our gain—and perhaps, someday, Nikolaj will gain the Iron Throne of Westeros. We'll be watching the third season of "GoT" to find out. (Prep is just as important to reaching your fitness goals. Try one of these 7 ways to ace your next race.)

From the May 2013 issue of Men’s Health.