A little more than three years ago, Kutcher read a script for a movie that would ultimately be titled "The Guardian."

"It was a really smart action movie script, which is something pretty rare in Hollywood these days," says Kutcher. "And I knew that Andrew Davis wanted to make it, and I think 'The Fugitive' (which Davis directed) is one of the great modern action movies.

"But if I'm being perfectly honest with myself, what I really wanted to do was make that next step ... to prove I could cut it. I was like Jake, the character I play, I guess. I had something I wanted to prove."

What Kutcher, 28, had to prove, put simply, is that he is more than the TV sitcom star ("That '70s Show") who made good in teen movies like "Dude, Where's My Car?" That he was more than the Gen-X goofball who created the MTV practical-joke show "Punk'd" and thrilled gossip columnists by marrying 43-year-old Demi Moore.

"I was figuring it was time I either put up or shut up," says Kutcher, who was replaced by Orlando Bloom in Cameron Crowe's "Elizabethtown," allegedly because he didn't have the acting chops. Crowe denies that, saying it became obvious after a few days of shooting that "I had simply miscast the role. I'd make another movie with him in a minute." Still, the rumors hurt more than Kutcher's pride. It hit him where he lives.

"It's a small town," says Kutcher, "where rumor becomes fact pretty fast."

Kutcher believed "The Guardian" was the film that could prove he had the goods. All he had to do, he says, was prove that he could hold a screen with Kevin Costner, and that he could convincingly play a Coast Guard swimmer.

"I was sweating both," Kutcher says. "Kevin was one of my acting heroes when I was young. So it was important for me to earn his respect. As for the swimming, I grew up in Iowa, you know? I earned my (swimming) badge in the Boy Scouts. ... I could make it from one side of the pool to the other."

Kutcher says he spent eight months training before filming began, just so he looked like he knew what he was doing before he arrived for the boot camp Davis had scheduled with real Coast Guard rescue swimmers.

"Working out in a pool is a whole lot different than being lowered into the ocean on a rope," Kutcher says. "But if I was going to make a movie that honored these guys who risk their lives on a regular basis to rescue strangers, I wanted them to at least know how much respect I had for what they do."