TORONTO - Georges St. Pierre is flying backwards, the victim of two well-placed kicks. And it's happened again and again.

It's not something that the UFC welterweight champion is used to in real life. But the 27-year-old mixed martial arts star from Montreal has taken his fight to the big screen where he is playing a villain in the action movie "Death Warrior."

St. Pierre is trading blows with Argentine actor-kickboxer Hector Echavarria, who is Death Warrior's star, writer and executive producer. Smoke billows from one corner of the set in a north Toronto warehouse as director Bill Corcoran watches the action from behind a bank of monitors.

St. Pierre rushes at Echavarria, swinging away with air punches. He drives the Argentine back to a caged fence and then Echavarria gets the upper hand, sending the fighter backward with one kick before flying through the air with another.

"Good," said Corcoran when the scene ends, then adds: "Worth doing again."

St. Pierre is more than happy to oblige. He's enjoying himself. During a break, he munches on a sandwich and marvels at how closely his double resembles him.

The Canadian fighter had a small role in "Never Surrender," another MMA film featuring Echavarria due out on DVD next month. This role is a little larger but still modest. Echavarria loaded both movies with fighters -- bringing UFC light-heavyweight champion Rashad Evans, Quinton (Rampage) Jackson and Keith (The Dean of Mean) Jardine into this film.

"All the fighters have been terrific," said Corcoran. "I think partially because of their training, they're very disciplined. . . . They've got tremendous command of their bodies."

The producers are trying to make it easy for the athletes to fit in. They're not expecting Sir Laurence Olivier on set.

"I think the biggest thing with the fighters is don't act, just be yourself and don't try and push it, that film is a very intimate medium and we will see what's going on in your mind," Corcoran explained. "And to try and look at each and every scene and give them something to hang onto, so that they have a motivation, they have a reason for being there and an understanding. And that makes it pretty easy for them. They seem to take that into their bodies and into their mind and be able to do something with it."

Added Echavarria: "Basically I wrote it so they're playing themselves, so it's much easier to do the part."

The plot is simple, according to the film's official website (www.movieset.com/deathwarrior).

"A gritty MMA fighter is forced into a twisted, underground gambling ring in which he must fight to the death with other MMA fighters in order to save his wife from certain death at the hands of a maniacal crime boss."

It's one of a string of MMA-themed films. David Mamet's 2008 production "Redbelt" was one of the more reputable. Just like the sport itself, MMA fighters are finding themselves in demand.

Light-heavyweight Stephan Bonnar had a starring role in "Ultimate Champion," which features a variety of other fighters in cameos -- Gilbert Melendez plays a logger while Thierry Sokoudjou is listed as a cannibal.

Bonnar played world champion fighter and decorated war hero Troy Jennings, who finds himself battling a billionaire villain.

"Pretty much you kind of just pretend, you know," Bonnar said of his first-time acting experience. "You pretend you're this character, you do pretend fights. Yeah, it's a lot fun, it's different, you know.

"Every day, it was just fun, I was happy. I mean you do work long hours. You always hear actors say `Oh, you don't understand. It's such hard work.' And I'm like 'Man it was just a blast for me.' I go 'Hard work? Hard work is getting beaten twice a day every day for 10 weeks."'

"Never Submit" also featured a slew of fighter cameos from the likes of Ken Shamrock, Mike Swick, Josh Koscheck, Nate Quarry, Cung Lee and Mauricio (Shogun) Rua.

Former middleweight champion Rich Franklin starred alongside Tiffani Thiessen in 2008's "Cyborg Soldier." Former light-heavyweight champ Chuck (The Iceman) Liddell snagged a cameo on "Entourage." Tito (The Huntington Beach Bad Boy) Ortiz had a guest shot on TV's "Numb3rs" and played a bouncer in the 2008 film "Zombie Strippers!" which featured his partner and movie veteran Jenna Jameson.

Not every fighter is keen on acting, however. Former light-heavyweight title-holder Forrest Griffin said his cameo on "Law & Order: Special Victims Unit" taught him that acting was not for him. He also joked they should have told him to bring some magazines, because he was bored out of his mind in his trailer.

"It's hurry up, wait, wait some more," he said.

"It is what it is, you know" he added. "It's easy money."

Former heavyweight champion Randy (The Natural) Couture has one of the longest acting resumes among fighters with credits including "Redbelt," "The Scorpion King 2: Rise of a Warrior" and television's "The Unit."

Fighter-turned-actor Oleg Taktarov ("Rollerball," "We Own the Night," "Righteous Kill") has also carved out a career in front of the camera.

Jardine, meanwhile, also has roles in the Jason Statham film "Crank High Voltage," due out in April, and "Game," which stars Gerard Butler and is slated for release in the fall.

Middleweight Michael Bisping did his bit to join the fold when, interviewed in the cage after a win, he said he was open to some film work if director Guy Ritchie, a fellow Brit, was listening.

St. Pierre definitely wants to do more acting.

"Absolutely, but with my fighting career I have to limit myself to small roles," he said. "I think it's going to be a good after-career for me."

Echavarria, 39, hopes his films can help St. Pierre and others accomplish that goal.

"Because I was a fighter and when you are a fighter, when your career is over, you really don't know what is going to happen. A lot of my friends that are fighters ended up in really bad situations. And (I thought) well maybe not only I can portray the martial arts in a great film but also I can give the opportunity to my fellow martial arts to have another career and to be able to use this as a stepping stone when their fighting career is over."

Echavarria combined acting and fighting, becoming his star in his native Argentina via the TV show "Brigada," a Latin American version of "The A-Team."

He credits martial arts for his success, having been very sick as a child with severe asthma. Then a Chinese acupunturist introduced him to martial arts.

"Martial arts saved my life," he said. "I owe everything to the martial arts and everything else that I accomplished later on in my life, I think it's because of the discipline, respect, sacrifice and all those values that you need to have in order, I believe, to be successful."