LOS ANGELES >> Mike Tyson stepped onto a spotlighted stage Friday and weighed in at 220 pounds, ripping off his shirt to reveal a muscled torso that could belong to an athlete of half his 54 years.

The former heavyweight champion moved into a COVID-protective glass box and went nose-to-nose with Roy Jones Jr., once the most talented fighter in the world. Jones’ 210-pound frame was slightly less toned, but still clearly in better condition than most of his fellow 51-year-olds.

These two boxing greats are older, calmer men now, but they’re returning to the ring Saturday night intending to recapture a moment of their brilliant past — and they’ve both worked very hard to make sure they won’t be embarrassed in this extraordinary boxing exhibition.

“This is the fun part,” said Tyson, who will fight for the first time in 15 years. “Everything else to get here was hell.”

Their fight at Staples Center is an eight-round sparring session of sorts. It will have two-minute rounds, no official judging and limited violence, although the limit depends on whether you’re asking the California State Athletic Commission or the fighters, who both intend to let their hands go.

“Maybe I don’t know how to go easy,” Tyson said. “I don’t know. I don’t want to say the wrong thing. I don’t want the commission mad at me.”

But for Tyson and Jones, this unique pay-per-view show is less of a sporting event and more of a chance for two transcendent athletes to prove age is a number — and aging is a choice.

“I don’t look at life as age,” Tyson said. “I look at life as energy. You don’t bring your age to the table. You bring your energy to the table. You don’t go meet people: ‘Hey, I’m Bob. I’m 59.’ You don’t do that.”

Tyson still seems surprised by the wave of events that carried him back to the ring. He admits the younger Tyson never would have believed he would be a middle-aged husband and father who needed to lose 100 pounds two years ago, because that headstrong kid from Brooklyn had never thought that far ahead.

“I didn’t even think I would live this long,” he said. “I was just so intense, and just took myself so serious.”

Tyson got back into shape at the urging of his wife, who got him to start doing 15 minutes a day on the treadmill. The 15 minutes turned into two hours, and then expanded to biking, running and eventually punching, along with the adoption of a vegan diet.

“Never eat anything,” he said with a laugh. “Just starve and exercise.”

The momentum started when he posted video of a training session on social media early in the coronavirus pandemic, and his crisp, powerful punches led to millions of impressions and a subsequent stream of increasingly lucrative comeback offers, along with the chance to raise money for charities.

“This is a part of my life that I had pretty much thrown away,” Tyson said. “My last fight, I didn’t have any interest in doing it. I’m interested in doing it now.”

Tyson is referring to his loss to journeyman Kevin McBride in 2005, when he finally wrapped up his singular career in ugly fashion. He became the heavyweight champion at 20 and reigned over the division for five years, but his epic downfall soured him on the sport.

“I want to do it now,” Tyson said. “Most of the time I was obligated to do it from a contract perspective: ‘If you don’t do this, we’ll take everything you have, and you’ll be back in Brownsville.’ They were blackmailing me. It’s a different perspective now.”

While Tyson became an international icon for his brutish, dangerous image and numerous misbehaviors, Jones was widely revered as perhaps the most skilled boxer of his generation. Jones was a preternaturally gifted athlete who dominated his weight classes while still pursuing his passion for basketball.

Nate Robinson was a rookie guard for the Knicks in 2005 when Jones participated in a full practice with the team.

“I was freaking out,” said the 36-year-old Robinson, no stranger to freakish athletic feats as a three-time winner of the NBA Slam Dunk contest at 5-foot-9. “That was one of the highlights of my life, to be able to rub shoulders and hoop with one of your favorite boxers.”

Jones fought regularly throughout the 2010s, but thought he was finally retired two years ago. When he got an offer to be the opponent in Tyson’s comeback, Jones couldn’t resist the chance to fight a legend he never got to meet during a career spent mostly at light heavyweight.

So Jones embarked on his own comeback training regimen.

“It’s been the craziest thing you ever could have imagined,” Jones said. “I can’t believe I’m able to maintain my speed at 51 years old. I’m still faster than 95% of the boxing world, and it shocks me. The aches and pains are there because you’re 50, and they’re going to be there no matter what you do. You just have to have a mental strength to overcome an adversity.”

Tyson and Jones are returning to a new world of boxing fandom and consumption. This show is being promoted by Triller, a video-making app and social media platform, with a fight-night show featuring performances by several rappers, a surprisingly solid undercard and a co-main event pitting Robinson in his professional boxing debut against YouTube star Jake Paul.

Robinson and Paul both seem appropriately awed by the circumstances of their bout.

“You’ve got to remember, I’m 23, and this is the first time that people my age will be able to experience a Mike Tyson fight live,” Paul said. “I can’t believe I’m a part of it.”

Neither Tyson nor Jones is likely done with boxing after this show. Jones said he hopes to fight mixed martial arts legend Anderson Silva next “if this one goes well,” while Tyson will go wherever this strange trip takes him next.

“Me being here is already a success,” Tyson said. “Me just existing as a human being is a success.”