Max Kellerman describes Conor McGregor as a "pure puncher" but doesn't believe that he will connect on a single punch against Floyd Mayweather. (0:59)

When UFC superstar Conor McGregor secured a boxing license in California in February as part of his efforts to land a mega boxing match with Floyd Mayweather, former two-division world titleholder Paulie Malignaggi was one of his biggest critics.

Floyd Mayweather vs. Conor McGregor Where: T-Mobile Arena, Las Vegas

When: Saturday, Aug. 26

TV: Showtime PPV, 9 p.m. ET

Malignaggi ridiculed McGregor on social media, at one point telling him he was "going to knock the beard off you homie. You are going to be apologizing for everything you have been trying to do to get into boxing."

Fast forward five months and, oh, how times have changed.

First, the unthinkable is happening. The all-time great Mayweather (49-0, 26 KOs) is exiting a two-year retirement at age 40 to face the 28-year-old McGregor in his pro boxing debut. They are scheduled to meet in a massively hyped 12-round junior middleweight fight on Aug. 26 (Showtime PPV) at the T-Mobile Arena in Las Vegas.

And maybe even more improbable than the fight being made is this: Malignaggi will soon be headed to training camp to serve as one of McGregor's main sparring partners to help ready him for the combat.

Say what?

Even Malignaggi is surprised that McGregor has invited him to camp.

Last month, Dean Byrne, an Irish welterweight Malignaggi used to train with in Los Angeles, and with whom he has been friends for years, got in touch with him. Byrne's brother, Gerry Byrne, works with McGregor and Dean was reaching out to Malignaggi at his brother's behest to see if Malignaggi would be interested in sparring with McGregor in preparation to fight Mayweather.

"I told him, sure, pass along my number. If they want to spar, let me know. I haven't been training but I could get in shape," Malignaggi said. "Nobody called and I forgot about it."

"When he got his boxing license in California, I was one of the guys calling him out and talking crap. I admit that. So I was really surprised they called me. He's putting his pride aside to maximize his opportunity to win this fight. They wanted me for my boxing ability and my boxing brain." Paulie Malignaggi

Then, on June 18, Malignaggi was at the airport in Las Vegas headed home to New York after having worked the British telecast of the Andre Ward-Sergey Kovalev light heavyweight title rematch the previous night, when his phone rang.

It was Gerry Byrne asking if he would be interested in helping McGregor get ready for the big fight.

"I told him I wasn't in great shape, but let me talk to my team," Malignaggi said. "I spoke to my team, they gave me the OK and I told Gerry, OK, let's make a deal and work this out and I would go to camp with McGregor."

Malignaggi won world titles at junior welterweight and welterweight and faced many big names, including Miguel Cotto, Ricky Hatton, Zab Judah, Danny Garcia and Adrien Broner. But he is now best known as a boxing commentator on Showtime in the United States and Sky Sports in the United Kingdom. In fact, he was already retired from the ring when Gerry Byrne called him.

Malignaggi (36-8, 7 KOs), 36, traveled to London on March 4 and got knocked out in the eighth round by Sam Eggington. Two days later, on March 6, the 19th anniversary of his first boxing match as an amateur, Malignaggi announced his retirement.

He has no plans to return to the ring as an active fighter, saying he will leave it at sparring with McGregor.

Former two-division boxing titleholder Paulie Malignaggi will help UFC lightweight champion Conor McGregor get ready for his megafight against Floyd Mayweather. AP Photo

"I've started working out because I need to be in some shape for the sparring," Malignaggi said. "McGregor has been training in Ireland but in a few more weeks when they come to Las Vegas is when I will join him in camp. It looks like that's the plan."

Malignaggi said any negative comments he may have made about McGregor's attempt to box one of the all-time greats in his pro boxing debut have been forgotten. Now, his goal is help the man be as prepared as he can for what most view as an unwinnable fight.

"I was a speed and reflex fighter, so is Floyd, so there's that," Malignaggi said. "I think they also picked me for my boxing brains and to give my two cents. If I'm there I'm there to help and do my part to improve him and get him ready for this big opportunity. I'd like to think there were several different reasons I was called. I am looking to make things happen for him."

"I'm not your average sparring partner because the competitive part of my career is over. I am going there to be of help to him, not to make a name for myself. I expect the sparring sessions to be intense. I am going there to improve the fighter so he can be as ready as he can for his fight." Paulie Malignaggi

Malignaggi said he and McGregor have never met, so when he arrives at camp it will be the first time. He said McGregor is showing how serious he is about giving himself the best chance to perform well against Mayweather by hiring one of his most vocal critics.

"When he got his boxing license in California, I was one of the guys calling him out and talking crap," Malignaggi said. "I admit that. So I was really surprised they called me. He's putting his pride aside to maximize his opportunity to win this fight. They wanted me for my boxing ability and my boxing brain.

"I think it really shows Conor's willingness to win in that he is ready to do what he has to, including swallowing his pride, by having his team call me. In that way it made me respect him more."

McGregor is a massive underdog in the fight, so even if Malignaggi is not expecting him to pull off the upset he at least wants to help him as best as he can.

"I think at the end of the day you're looking to make improvements in him," Malignaggi said. "Winning the fight is up to Conor. I want to see improvements and I want to make him better than he would have been without me in camp. I will do my part.

Paulie Malignaggi, left, has fought great competition during his boxing career. Al Bello/Getty Images

"I'm not your average sparring partner because the competitive part of my career is over. I am going there to be of help to him, not to make a name for myself. I expect the sparring sessions to be intense. I am going there to improve the fighter so he can be as ready as he can for his fight. I'm not going to do it so much for the money but because I believe this is the biggest sporting event of the year with the Super Bowl and the Champions League final in soccer. This is the biggest boxing event of the year."

Malignaggi admitted a McGregor win is a long shot.

"Realistically, to ask Conor to win the fight is a big ask," Malignaggi said. "But maybe he can win moments of the fight or certain rounds. If he's winning certain moments of the fight, even if he loses in the long run, people will talk more about what Conor did than Floyd winning."

Working with McGregor in training camp will also give Malignaggi a unique perspective when it comes to fight night. He will be working the Showtime PPV telecast as an analyst and will certainly know what McGregor showed him in camp. He also has called several of Mayweather's bouts.

"On fight night I will be able to share a lot of things," Malignaggi said. "It will make for some pretty cool stuff talking up the fight. It's exciting to be part of possibly the biggest sporting event of the year. I didn't expect it and gives me a reason to get in shape."

Your take?