One of Floyd Mayweather's former sparring partners has labelled his lucrative August showdown with Conor McGregor a "whitewash" - and says the build-up will be better than the fight.
Mayweather, 40, retired in 2015 with an unblemished 49-0 professional boxing record while boastful Irishman McGregor, 28, is the UFC's lightweight champion.
Meanwhile, Conor McGregor is the best that MMA has to offer and the first fighter in the history of the UFC who won held two championship belts at the same time.
Mayweather's 2015 victory over Manny Pacquiao broke all pay-per-view records, with 4.6 million people purchasing the $99.95 (£65) HBO / Showtime broadcast.
"This is a fight where all the Hollywood and National Basketball Association stars will come out, you know..."
UFC president Dana White described it as "the impossible deal is now done" after bringing the biggest names in boxing and UFC into the ring.
"It's two different sports trying to be one sport", said boxing great Leonard. That means you'd have to bet $1200 on Mayweather to win $100 if he wins.
Smith also stated that Mayweather's attraction to a fight with McGregor is the Irish man's ability to promote his fights. The fight will take place in a boxing ring and be governed by boxing rules. This fear was that they may never see Conor McGregor fight in the UFC again.
Rumors and reports of a fight have been floating for nearly a year, with both fighters openly acknowledging a potential bout. Muscle memory, and natural instincts, could easily take over when McGregor fights, but his contract now forbids him from doing so.
Most observers are less impressed and do not expect the fight to be competitive: Mayweather was listed as a -1100 favorite at the Westgate Las Vegas SuperBook, meaning bettors would have to risk $1,100 on Mayweather to win just $100.
Their pay-per-view fight is expected to generate huge amounts of money.
The T-Mobile Arena seats 20,000 for boxing and MMA events.