We have no doubt there'll be plenty of this from both men before they fight, but what really matters is who does the talking in the ring on Saturday, August 26 in Las Vegas.
Mayweather, who is widely recognized as one of the greatest boxers of all time, retired undefeated in 49 professional fights.
Both men had previously said they wanted $100m (£78m) each for the fight and negotiations have gone back and forth for about a year. Floyd is very opinionated on a lot of things and he's a smart guy surrounded by smart people.
Though Las Vegas oddsmakers have made Mayweather a heavy 10-1 favourite, the thought of the fight has excited many in the MMA world.More news: Rep. Scalise upgraded from "critical" to "serious condition"
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Mayweather reportedly earned approximately $330 million for his victory against Manny Pacquiao in 2015, and the fight against McGregor is expected to shatter any gate and pay-per-view records, according to news.com.au. Promotion for the event will be handled by Showtime, although the UFC will run its Embedded series during the fight build-up.
McGregor, 28, is 21-3 in UFC fights, with his most recent fight coming in November against Eddie Alvarez.
He won the UFC's featherweight title in a 13-second knockout of Jose Aldo on December 12, 2015. However, it's still very probable that this fight could go down as one of the most expensive in the history of the sport. It finally came together over the last few days, and Nevada boxing officials on Wednesday approved the date for a Mayweather Promotions bout.
"He will go after Floyd Mayweather and he will try to knock him out".