Floyd Mayweather looks to improve an immaculate professional record to 50-0 in the early hours of Sunday morning when he takes on Ireland's UFC superstar Conor McGregor.
The brash personalities will settle their differences at the T-Mobile Arena in Las Vegas in a cross-code event that has captured the imagination - even though McGregor has never previously boxed in the paid ranks.
Here, we look at some of the details surrounding this weekend's extravaganza.
HOW CAN I WATCH THE FIGHT?
The event will be broadcast on Sky Sports Box Office at a cost of €24.95 in the Republic of Ireland. If that sounds steep, then it is worth remembering that punters across the pond will have to fork out $89.99 for standard definition and $99.99 in HD to watch the light-middleweight contest on Showtime.
WHAT TIME WILL IT START?
It is difficult to say for certain, but it would be worth going to bed and setting an alarm rather than trying to stay awake if Mayweather-McGregor is the only bout that appeals as the main event will not start before 4am. A reasonable guess would be around 5am - but it may even be 5.30am when the first bell sounds.
WHO ELSE IS ON THE BILL?
Wales' Nathan Cleverly defends his WBA world light-heavyweight title against Badou Jack, a fighter promoted by Mayweather who defeated George Groves and drew with James DeGale in his run as WBC super-middleweight champion. Elsewhere, Mayweather protege Gervonta Davis makes the second defence of his IBF super-featherweight title against Francisco Fonseca, while Middlesbrough's Savannah Marshall, who has competed at the past two Olympics, makes her professional debut in the super-middleweight division against Sydney LeBlanc.
TALE OF THE TAPE
Mayweather - McGregor
40 Age 29
49 Fights 0
49 Wins 0
26 KOs 0
0 Draws 0
0 Losses 0
387 Rounds boxed 0
5ft 8in Height 5ft 9in
Orthodox Stance Southpaw
72in / 183cm Reach 74in / 188cm
89 Number of swear words used on press tour 84
7.4m Twitter followers 5.5m
5.5m Twitter mentions since June 14 8m
99,000 Most retweeted tweet since June 14 253,000
£265m Reported estimated wealth £26.5m
* Twitter data from official Twitter media release.
HOW THE FIGHT CAME ABOUT
July 2, 2015 - Appearing as a guest on television programme Conan, Dublin's McGregor told host Conan O'Brien, referring to Mayweather: "I would box him if the opportunity arose."
December 30, 2015 - Mayweather responds for the first time, and their rivalry begins to grow, when he tells FightHype.com: "They say he talks a lot of trash and people praise him for it, but when I did it, they say I'm cocky and arrogant."
January 8, 2016 - On the suggestion they are treated unequally, McGregor, now 29, wrote on Facebook: "Don't ever bring race into my success again."
May 6, 2016 - Several months had passed in which McGregor even took to Twitter to insist he was retiring when The Sun reported the two were close to agreeing what would be a lucrative fight. However Dana White, president of the UFC, swiftly responded to insist: "It's not true."
May 8, 2016 - McGregor further raised the prospect of the match-up when, amid the build-up to Amir Khan's defeat to Saul Alvarez in Las Vegas, he wrote on Twitter: "MMA versus boxing."
May 13, 2016 - Mayweather responded by telling Showtime, the television network he has long fought on: "Hopefully we can make the fight happen. He's no pushover."
November 30, 2016 - Following six months in which many observers remained sceptical and suspected the publicity-hungry fighters were attempting to further build their already significant reputations, McGregor was granted a boxing licence in California.
January 11, 2017 - The public negotiations begin with Mayweather offering the Irishman 15million US dollars to fight him, and then White within 48 hours offering each fighter 25million US dollars.
February 15, 2017 - America's Mayweather, so often determined to remain in control of any significant announcements via social media, writes on Instagram: "There hasn't been any deal made in regards to a fight between myself and any other fighter."
February 16, 2017 - Mayweather starts as a 25-1 favourite to win the potential fight as the first betting lines come out.
March 8, 2017 - While in London to promote a fight between his protege Gervonta Davis and Britain's Liam Walsh, Mayweather tells McGregor via ESPN: "Sign the paper. You said you were the boss, just sign the paper and let's make it happen."
March 10, 2017 - Speaking on his Undefeated tour, Mayweather further builds excitement and speculation by saying: "I'm coming out of retirement just to fight Conor McGregor. Let's fight in June."
March 15, 2017 - White, also appearing on Conan and therefore almost bringing the saga full circle, says: "I do think it's going to happen. There's so much money involved, I just don't see how it doesn't happen."
April 16, 2017 - While posting an image of him wearing boxing gloves, McGregor writes on Instagram: "Join me in the preparation of my next fight, being announced very soon."
April 20, 2017 - He then posts another of him shadow boxing, with the caption: "Floyd may crap his jocks after all and if so I will go back to true fighting or just pick another boxer like Manny (Pacquiao) or something."
May 8, 2017 - McGregor and White agree terms to fight Mayweather, nearing the conclusion of the deal the Irishman has long pursued.
May 20, 2017 - Speaking at the post-Davis-Walsh press conference in London, Mayweather becomes the centre of attention and again talks up the possibility of the Mayweather-McGregor match-up.
May 21, 2017 - Despite a hope that they are nearing an agreement, McGregor writes on Twitter: "Sign your end Floyd or you are just a mouth."
June 5, 2017 - The biggest fight of 2017 between two professional boxers, Gennady Golovkin and Alvarez, is announced for Las Vegas' T-Mobile Arena on September 16, potentially affecting Mayweather-McGregor. The American has long favoured fighting in May and September, and the T-Mobile Arena has become Vegas' favoured fight venue.
June 14, 2017 - A boxing match between Mayweather versus McGregor is finally signed for August 26 at the T-Mobile Arena.
