So, what *is* the truth about Conor McGregor being knocked out in sparring ahead of his fight against Floyd Mayweather on August 26?

The rumour of Notorious suffering an embarrassing KO has spread like wildfire across social media over the past few days.

It was suggested that McGregor had been floored by lightweight boxer Brandon Rios, although this was later mis-reported as British MMA fighter Bradley Wheeler.

"He got knocked out in sparring already, man!" former world champion Jesse Vargas, referring to Rios, was quoted as saying by the Mirror.

“The boxing world is small; it's a small circle.”

If true, it’s hugely encouraging news for Mayweather, one of the greatest boxers of all time.

Although the 40-year-old hasn’t fought since defeating Andre Berto back in September 2015, the bookmakers have him down as the overwhelming favourite to triumph at the T-Mobile Arena in Las Vegas next month.

Mayweather reacts to the McGregor KO rumour

Fight Hype, per ABS CBN News, have been in touch with Mayweather this week to get his thoughts about the rumours involving McGregor - and the American has reacted perfectly.

“My take is if I ain't seen no footage, I don't believe it,” he said during a phone conversation, suggesting he doesn’t buy the claims.

“We're working on Vargas to sign with Mayweather Promotions, so we've been communicating.

“But everything is just rumour until I see it. I have to see [the knockout] with my own eyes.”

Listen to Mayweather give his opinion here…

Mayweather, with his vast experience, clearly knows better than to believe an unfounded internet rumour about his next opponent.

If the undefeated boxing legend allows himself to believe McGregor was knocked out in sparring, he runs the risk of underestimating the Irishman ahead of a fight that would tarnish his legacy if he loses.

McGregor's team and Rios have denied the rumour

The Telegraph, meanwhile, have exclusively revealed that McGregor’s management team have denied any truth in the rumour - as you’d expect them to.

McGregor’s management told the Telegraph: “The guy mentioned by Jessie Vargas is Brandon Rios, not Brad Wheeler. Neither have sparred with Conor."

"The world's gone crazy," Rios was quoted as saying on Monday.

"My phone's been blowing up. I've been getting texts messages and calls about this. I've never met McGregor, and I don't know who he is."

It’s safe to say we can put that rumour to bed now.