LOUISVILLE, Ky. -- Gary Stevens compares his acting debut in the upcoming "Seabiscuit'' movie to putting an apprentice jockey on the favorite for the Kentucky Derby: a real gamble.

Playing jockey George Woolf was hardly a stretch for the Hall of Fame rider with three Derby victories. But sharing the screen with Hollywood heavyweights Tobey Maguire, Jeff Bridges and Oscar winner Chris Cooper was a challenge.

"They got a movie that had a $98 million budget, and here they hire me, and I've never acted before,'' said Stevens, who credits screenwriter Gary Ross for taking a chance on him.

"Gary never was nervous about the situation, but I'm sure the producers were very concerned. Gary had a lot of confidence, which gave me a lot of confidence.''

Stevens feels just as strongly about Buddy Gil, his mount in Saturday's 129th Derby. The colt has won his last three races, including the Santa Anita Derby over Indian Express, another Derby horse.

"He's got the same kind of heart that Silver Charm had,'' Stevens said, referring to his most recent Derby winner, in 1997. "But athletically I think he's probably a little more endowed than Silver Charm was.''

"Seabiscuit,'' about a racehorse who captured America's imagination in the 1930s, comes out in July.

"It's the first thing I've ever done outside of racing that gives me the same feeling of satisfaction that winning a race does,'' he said.

"I get an adrenaline rush by doing a scene. The feeling of satisfaction when you nail a scene and you see the smile on the director's face is a lot like winning a race and seeing the smile on a trainer's face.''

Stevens has made a lot of trainers smile. His mounts have earned more than $200 million since his first thoroughbred winner in 1979 in his native Idaho.

Jeff Mullins, who trains Buddy Gil, has been friends with Stevens for more than two decades. He smiles at the image of Stevens walking a red carpet in Hollywood.

"Gary is just an ordinary guy,'' Mullins said. "He's just like anybody.''

Stevens retired in December 1999 because of arthritic knees but returned the following fall. Although medication dulled his knee pain, Stevens is selective about the number of races he rides.

Acting came along just in time.

"It's a heck of a lot easier on my body than riding race horses,'' he said. "When you're 40 years old, and you get a new career opportunity -- that doesn't happen very often.''

Stevens took five months off from riding last year to film "Seabiscuit,'' but his business picked up where it left off when he returned.

"I didn't expect to pursue this,'' he said, referring to the big-screen career. "I thought it was probably going to be a one-shot deal.''

Instead, the 5-foot-3 Stevens -- "It's one of the great things about film, nobody knows how tall you are,'' he said -- figures he can mix riding with acting.

He already is considering two scripts for non-racing movies that would start filming in September. One of them calls for him to play "a bad guy with a little bit of compassion.''

Stevens believes "Seabiscuit'' will give the public a better understanding of jockeys, who often aren't appreciated as athletes controlling 1,000-pound animals at 40 mph.

"The movie is going to touch a wide variety of personalities. There's a lot of emotion in it. If a person comes out of this film without crying at least four times, they're not a human being,'' he said. "It's going to be great for our sport.''