Why is a UFC star fighting a boxer?
A pertinent question.
The undefeated Floyd 'Money' Mayweather will face UFC icon Conor McGregor in a boxing match which is already being described as 'The Fight of the Century' - but you would be forgiven for asking 'great, but why?'
Each man will have their different reasons for taking the fight, but the huge sum of money both fighters stand to make will be a considerable motivation.
McGregor Mayweather countdown (set for 4am BST start)
It's estimated that the two could earn as much as $100m from the bout, although it's generally accepted Mayweather will receive a greater share of the fight purse given his superior reputation as a professional boxer.
Both fighters are renowned for their showmanship and the opportunity to earn a multi-million dollar paycheck was too good to ignore.
Floyd Mayweather v Conor McGregor world press tour - in pictures
Both fighters have, arguably, achieved all they can in their respective disciplines.
Floyd Mayweather remains unbeaten in his career, winning 49 fights with 28 of those coming by knockout.
Why has McGregor come out of retirement?
Well technically he never officially retired from UFC. McGregor causes a huge furore when he posted a short statement on Twitter, appearing to announce his retirement.
"I have decided to retire young. Thanks for the cheese. Catch yas later," McGregor wrote.
I have decided to retire young.
Thanks for the cheese.
Catch ya's later.
— Conor McGregor (@TheNotoriousMMA) April 19, 2016
Dana White, the president of the UFC, then announced he had pulled McGregor from his hotly anticipated rematch with Nate Diaz in July because of a reluctance to promote the fight.
“I am still ready to go for UFC 200. I have become lost in the game of promotion and forgot about the art of fighting,” McGregor wrote in a statement on his Facebook page.
“There comes a time when you need to stop handing out flyers and get back to the damn shop.
“Fifty world tours, 200 press conferences, 1 million interviews, 2 million photo shoots, and at the end of it all I’m left looking down the barrel of a lens, staring defeat in the face, thinking of nothing but my incorrect fight preparation. And the many distractions that led to this.
“Nothing else was going through my mind. It is time to go back and live the life that got me this life. Sitting in a car on the way to some dump in Connecticut or somewhere, to speak to Tim and Suzie on the nobody-gives-a f***-morning show did not get me this life.”
Since that date McGregor avenged his defeat to Nate Diaz with a points decision win before beating Eddie Alvarez to win the Lightweight title.
Why is Floyd Mayweather coming out of retirement?
Floyd Mayweather on the hand is coming out of retirement to return to the ring - for the second time in his career.
Mayweather first retired in December 2007 following a points victory over Ricky Hatton Las Vegas.
Following a 21-month absence from boxing, Mayweather returned to the ring to fight Juan Manuel Marquez.
His victory over the Mexican was followed up by a nine-match winning streak that saw him beat, among others, Saul Canelo Alvarez, Shane Mosley and Manny Pacquiao.
Mayweather retired for a second time after beating Andre Berto on September 12, 2015.
In January 2016, Mayweather insisted he would only return to the ring to fight take a fight with Conor McGregor.
"Only thing I'm probably interested in is the Conor McGregor fight," Mayweather said. "I'm a businessman, and it makes business sense. I believe in what me and [adviser] Al Haymon talk about every day."
Is there a title at stake?
There is no official belt on line.
Despite being a five-division world champion, Mayweather does not actually hold any world title belts - so there will be no championships on the line.
McGregor is currently the Lightweight champions of the world in UFC but it is not thought the Irishman will have to vacate his belt in order to fight Mayweather.
This is purely an exhibition match for the entertainment of fight fans, as well as for the benefit of both fighters' bulging bank accounts.
Who stands to profit?
Both men do. Handsomely.
Earlier this year, when rumours that a fight was in the offing began circulating, Mayweather implored McGregor to accept a $15m deal.
"We tried to make the Conor McGregor fight," Mayweather said.
"They know what my number is. My number is a guaranteed $100 million. That was my number.
A post shared by Floyd Mayweather (@floydmayweather) on May 26, 2017 at 5:02am PDT
"We are willing to give him $15 million and then we can talk about splitting the percentage -- the back end -- on the pay-per-view. But of course, we're the 'A side.' How can a guy talk about making 20 or 30 million if he has never made 8 or 9 million in a fight."
Let's go get some boxing ones now son. pic.twitter.com/KwBkFriTto
— Conor McGregor (@TheNotoriousMMA) May 18, 2017
Mayweather and McGregor then continued to publicly flirt with the idea of a super fight before the Irishman finally revealed in May that he had signed a contract to meet 'Money' in the ring following months of negotiation and speculation.
While Mayweather has nothing left to prove in the world of boxing, the fight is McGregor's chance to prove he is the best all-round fighter in combat sports.
Is there public appetite?
If the social media hype is anything to go by, this fight is set to be the biggest in the history of boxing.
The public love a bit of drama, and the prospect of seeing UFC icon Conor McGregor toppling the greatest pound-for-pound fighter in the modern era is going to get people interested.
Revenue from ticket sales and TV subscriptions for the fight are expected to net the fighters tens of millions of dollars, although it's hard to know how popular the fight will be until the week of the fight.
A post shared by Floyd Mayweather (@floydmayweather) on May 2, 2017 at 10:17pm PDT
Showtime Sports control the rights to broadcast the fight, however the cost of buying the fight on pay-per-view is yet to be revealed.
Those involved in the boxing industry have taken a very cynical view on the whole event.
10-time world champion Osca De Lay Hoya has described the fight as a "circus".
"You're going to ask McGregor to go inside a boxing ring, where he has no experience whatsoever," says De La Hoya.
"He's never laced up a glove. I call it a circus, I don't think it's fair for the sport of boxing."
De La Hoya also gave McGregor zero chance of taking Mayweather's undefeated record.
"What he needs to know is that I started boxing at five years old. I'm an Olympic gold medalist. I'm a 10-time world champion in six different weight classes.
"Yes, I was a bit older when I faced Mayweather but even I couldn't beat him. So what makes McGregor think that he can go in there, in his very first professional fight, having really no experience in the professional ranks and beat Mayweather?
"It's kind of far-fetched. I would tell McGregor that it's the fight you don't want to take your first time around. This is obviously all about money.
"This is all about just creating the hype around this event that potentially can damage the sport of boxing once again like Mayweather-Pacquiao did."
WBA, WBC and IBF middleweight champion Gennady Golovkin echoed De La Hoya's contempt for the fight.
"This [Mayweather-McGregor] is not for fighters, but business," said the 35-year-old Kazakh.
"I think people understand what is a true fight, a boxing fight, like mine with Canelo or a big show, maybe sometimes for people a funny show, like a circus show.
"Everybody knows. Conor is not a boxer, just a show. If you want to watch a show please watch them, if you want to watch a true fight, a true boxing fight and you respect boxing, watch my fight with Canelo.
"This is business. Conor with Floyd is not a boxing fight because Conor is not a boxer. Money fight OK, show fight OK."
What are the betting odds?
Unsurprisingly the undefeated, multiple world title-winning professional boxer Floyd Mayweather is the favourite to win the fight.
However punters are hopeful that McGregor can pull off one of the biggest upsets in sport, with Irish bookmaker Paddy Power reporting 92 per cents of bets placed on the event are backing a McGregor victory.
Floyd Mayweather win by points 4/6
Floyd Mayweather win by KO or TKO 7/4
Conor McGregor win by points 40/1
Conor McGregor win by KO or TKO 7/1
Floyd Mayweather v Conor McGregor betting: Latest odds, best sign-up offers & suggested tips