After months of build-up and hype, the eye-watering Floyd Mayweather-Conor McGregor bout gets under way around 4am on Sunday morning at the T-Mobile Arena in Las Vegas.

The purse for this bout is astronomical; at 40-years-old Floyd ‘Money’ Mayweather will pocket an estimated $200million while UFC lightweight champion Conor McGregor is expected to take home $100million for his participation in the fight.

As attractive as a $200m payday is for Mayweather; former super middleweight title holder Carl Froch has warned the undefeated boxing legend that coming back from retirement might be a mistake.

Froch, resisted attempts to lure him back to the ring after he retired in 2014 by knocking out George Groves.

The Cobra, who enjoyed a 12-year career which yielded four world championships, was offered a lucrative contract to fight Gennady Golovkin.

Rob McCracken, the Cobra's coach advised the super-middle weight veteran to take a few weeks before making a final decision; it’s safe to say that was the right advice.

“I lasted two days,” Froch told the Daily Mail.

“On the second day, I went for a run and just stopped. I walked home. My back was sore, I had a stitch, my Achilles was killing me and I was blowing out my arse.

“I just thought what's the point? I could have come back and destroyed my legacy.”

Few boxers in history have a fight career that reads like Floyd Mayweather’s 49-0 - a record he currently shares with American heavy-weight Rocky Marciano (1947 - 1952).

It has been well publicised that the American wants to get past the 'The Brockton Blockbuster's' 49-0 record; taking the 40-year-old's fight record out to an unprecedented 50-0.

If McGregor somehow manages to best Mayweather early Sunday morning the American’s legacy will be in tatters.

Froch also stated that even a boxing great like Mayweather could suffer from ring rust.

“When I used to have a month out of the ring and go back to the England squad to spar with good amateurs, I could use my jab, experience, dictate the pace and have it all my own way. But I'd still be making mistakes, leaving my feet behind.

“Then I'd go home and I'd be aching - my shoulder would be gone, I'd have over-extended my elbow.

“You can't just go from nothing to competing at the top level.

“Mayweather will probably be thinking he's not competing at the top level, he's not fighting a boxer, so he'll be okay. It's very clever what he's done. He's come out of retirement for a fight that in his mind will be one-sided.

"But he may have just made a wrong move here.

“There's a lot at stake for Mayweather because of his legacy, but it's massive money. He's got a lifestyle where he's probably spending 10 million quid a week and he's got to try to maintain that.”