The Life of Hollywood: In front of the pretty face and dimpled cheeks, Mario Lopez puts up his dukes

Mario Lopez is sweating. And panting. And, if you look closely, grimacing.

As he stands in the corner of a boxing ring awaiting the bell that will signal the next round, the “Extra” host sways nervously in a pair of loose-fitting trunks that make his short legs seem even more compressed. The Crest-commercial smile he flashes while doling out celebrity palaver for the benefit of a syndicated-television audience is absent. In fact, Lopez’s mouth is nearly shut, the only thing visible through his slightly pursed lips is a mouth-guard specked with blood.

The lights shine harshly, as they do on the “Extra” set at the Grove. But this time there are no coiffed guests to banter with, no squealing fans to sign autographs for, no army of assistants to run out for one of his preferred meals, a calorie-conscious mix of sashimi and avocado. There is just one other man in the ring, and he doesn’t look happy.

Jimmy Lange, a professional middleweight, stands diagonally across from Lopez, jumping assuredly from side to side and loosening his neck muscles in the way professional boxers do. Lange has won 35 of his 40 pro bouts, more than two-thirds of them by knockout. He does not seem to know who Lopez is. He does not seem to care.

This is a charity fight in a makeshift ring inside the Beverly Hilton ballroom. For Lopez, though, it might as well be a championship card at the MGM Grand. All around the ring sit people he desperately wants to impress — well-known boxing promoters, and trainers, and even former fighters, people like Jake LaMotta, Ray “Boom Boom” Mancini and Micky Ward, the welterweight recently made famous by Mark Wahlberg in the film “The Fighter.” The setting also doesn’t lessen the pain of Lange’s haymakers.

The bell rings. Lopez charges, getting in a few jabs at Lange’s torso. The pro fighter tolerates them for a moment and then, in the let’s-get-this-over-with way that Harrison Ford draws his pistol on the swordfighter in “Raiders of the Lost Ark,” winds up for a punishing right hook. His punch lands squarely between Lopez’s cheek and jaw. The actor’s neck snaps back like a spring-loaded toy.

There are many ways a Hollywood pretty boy can find amusement. Getting in the ring with pro fighters to reinvent yourself as a boxer, as Lopez is doing, seems like perhaps the least pleasant.

Pretty much since he first set teenage girls’ hearts aflutter playing A.C. Slater — the mulleted, garishly attired Army brat of early ‘90s camp-hit “Saved by the Bell” — Mario Lopez has been ambivalent about his fame. He knew he was attracting a heavily female audience, fans who appreciated his harmless good looks and cheesy charm. This wasn’t entirely a bad thing. It was a Hollywood meal ticket, and it made finding a girlfriend a lot easier. But the teenybopper image, he thought, didn’t fit with either his working-class roots or his high school wrestling background. And it didn’t square with the serious actor he believed he could be.

“I’m not dumb. I knew my audience is mainly women,” Lopez said a few weeks after the Lange fight. “But I wanted people to see another side of me. I wanted men to see another side of me.”

After “Saved” and its ill fated spin-off, “Saved by the Bell: The College Years,” came to an end, Lopez embarked on a career odyssey of sorts. He starred in a horror film titled “A Crack in the Floor.” He did a multi-episode arc on “Nip/Tuck,” FX’s dark drama. He even took the lead role in a television biopic about gay Olympic diver Greg Louganis; he figured it wouldn’t win him any Emmys, but he hoped it would make America finally take him seriously.

It didn’t work. America preferred the smiling, dimpled Mario Lopez.

So Lopez developed another profile: as a purveyor of low-budget nonfiction entertainment. He can come off as pleasant in an empty sort of way, a kind of poor man’s Ryan Seacrest, and that appeal has secured him a very profitable niche. Turn on the TV most weekdays and you won’t have to wait long to see Lopez somewhere — on “Extra,” on MTV shows such as “America’s Best Dance Crew” or “MTV’s Top Pop Group.” Switch to the Latino-oriented Si TV and there he is again, co-hosting a dating program. This coming season he’ll host a celebrity-reality show on the CW called “H8R,” about tabloid personalities confronting their enemies.

There’s hardly a beauty pageant he hasn’t presided over — “Miss America,” “ Miss Universe,” Miss Teen USA.” And of course there’s “Dancing With the Stars,” on which he and partner Karina Smirnoff quickstepped their way to the finals in 2006.

But Lopez believes he’s simply fallen into the hosting jobs and the dancing competitions the way someone good with numbers might wind up an accountant. He has a different a passion that goes beyond any Hollywood job: boxing.

An ardent boxing fan who calls Oscar de la Hoya a close friend and also does TV commentary for the occasional pro fight, Lopez had been doing boxing workouts for a number of years. But he’d recently begun to up his game, trying his hand at actual bouts. And so last year, a longtime pal named Bert Marcus had an idea: Lopez should let people see him in a fighting light.

The 29-year-old Marcus is an up-and-coming documentarian — he produced a movie called “Teenage Paparazzo” directed by the actor Adrian Grenier about the celebrity-photographer relationship — and a motor-mouth showman who could come from the boxing world. Even his name seems right.

“Here’s what I said to Mario. I said, ‘You’ve got to do a documentary. You’ve got to show people a different side of who you are,’” Marcus said. “I mean, Mario’s a charming guy, but he’s also a gritty guy. A lot of these people are playing celebrity golf tournaments. He doesn’t do any of that.”

The actor hesitated at first. “Boxing is one of the only things I do alone,” he recalled. “I go to church alone, and I go to the [boxing] gym alone.” And even though Lopez was very accustomed to being on camera, he wasn’t used to being in front of one sweating and unsmiling.

But he had to admit the idea had its appeal. Lopez already had attempted to reinvent himself with audiences as a family man, signing on for a VH1 reality show with girlfriend Courtney Mazza about their impending parenthood. But he knew those efforts rarely up a celebrity’s standing. Indeed, when the show, “Saved by the Baby,” finally aired, Lopez came off as so hammy it prompted Gawker to snark “Sure, Mario Lopez now has a show called ‘Saved by the Baby,’ but who’s saving the baby from Mario Lopez?”

A boxing documentary, Marcus argued, could revamp Lopez’s public image. And if there’s one thing the “Extra” host understood, it was the importance of finessing one’s public image. Lopez finally agreed, and he and Marcus began traveling the boxing world.

They hung out at Manny Pacquiao’s Hollywood gym, interviewed fighting aficionados such as Arnold Schwarzenegger, talked to boxers like Sugar Ray Leonard and sought out actors who’ve played boxers, like Denzel Washington and Wahlberg. They spent dozens of hours together as Lopez trained, the actor torturing himself with long runs in the Hollywood Hills and at a boxing club in Burbank. The idea was to offer a window into the boxing world via its luminaries, but also through Lopez’s quest to join them.

“Mario’s a perfect vehicle. No would think of a Mario Lopez documentary about boxing,” Marcus said. “But Mario eats, drinks and breathes boxing. And I could use that to shatter people’s expectations.”

Marcus is now in the final stages of editing his film and is close to landing a distribution deal for a commercial release.

In footage that will be included in the film, personalities like Leonard and Washington underscore boxing’s ability to erase socioeconomic and other lines and say it plays to the underdog mentality that people in competitive fields such as acting use as motivation. “My whole life, I’m a Mexican kid from Chula Vista, and I was told I couldn’t make it in Hollywood,” Lopez said. “Even on ‘Saved by the Bell.’ ‘You’re too ethnic, you need blond hair and blue eyes.’” He pauses, reflecting generally about the sport. “Boxing had made me a man. You’re completely naked when you’re doing it.”

About six weeks after the Lange fight (judges declared it a draw), the actor is sitting in his trailer on the “Extra” lot. It is a luxurious space, decked out in rustic wood, a black leather couch and a sleek kitchen stocked with high-end liquor bottles. Adorning the walls are boxing gloves, magazine covers and crosses. Boxing and religion are everywhere, even in the bathroom, which features more wall accouterments.

So far, Lopez has fought six fights and won them all. He acknowledges they’re amateur bouts. “But here’s the thing,” he said. “These guys are giving me their best. Because, really, who wants to be beaten by a Hollywood kid?”

The whole enterprise, he said, has been character building. “It’s helped my confidence,” he said, and then in a moment of self-awareness adds, “Not that I’ve lacked for it.”

For all the appeal of boxing as a sport, one also gets the sense that Lopez sees in it a specific message of encouragement. Reality television is evanescent; a star one minute is often gone the next. But in boxing no one is ever truly over the hill. Evander Holyfield won a title at 47. George Foreman retired and unretired so many times he made Brett Favre seem decisive.

“You see what Bernard Hopkins did?” Lopez said, growing animated as refers to the light heavyweight’s title win last month at 46. “They said he was too old, and that everyone else was younger and faster. But Hopkins was craftier.”

Leonard told interviewers for the film that he respects Lopez because the “passion he has for the sport [is] unlike any actor I’ve seen. To get in the ring when you don’t have to and risk the injury that he does is unbelievable.”

Others around Lopez, however, have been less than enamored with his new pursuit, recalling the way boxing has taken a toll on actors such as Mickey Rourke. Lopez’s manager and “Extra” producers have repeatedly warned him that boxing could ruin his most precious asset — his face.

“Every time he goes into the ring, I say there goes my moneymaker, and my show flashes before my eyes,” “Extra” senior executive producer Lisa Gregorisch-Dempsey said.

The concern isn’t entirely misplaced. During sparring once, a stray elbow opened a gash in Lopez’s head. He went to the hospital, where doctors told him he’d require nine staples. But when he was told his head would have to be shaved to perform the procedure, Lopez had them do it a different way — he had to shoot “Extra” the next day.

Lopez’s level of enthusiasm about the sport has kept his spirits high when others around him have been less supportive. At the Lange fight, after Lopez has showered he comes out to the ballroom to meet his girlfriend and Marcus. There is little evidence of a man who has just been beaten pretty hard.

“I did think for a minute he was going to kill me,” Lopez said. He is back in full smiling mode now. “I can’t believe I’ve fought him. Man, three rounds with Jimmy Lange,” he continued, growing impressed. “I’ll be thinking about that on-set tomorrow.”

steve.zeitchik@latimes.com