Conor McGregor and Dustin Poirier will go up against each other for the third time in the early hours of Sunday morning.
Here is everything you need to know about the fight.
Where is it and what time does it start?
UFC 264 takes place in the T-Mobile Arena in Las Vegas, with a full crowd expected as Covid regulations have been eased in the US state.
The first fights of the night are scheduled to start at 11pm on Saturday night with the main preliminary fights starting 1am Irish time.
The main undercard will start at 3am Irish time and McGregor due in the octagon between 5am and 6am.
Where can I watch it?
BT Sport 2 will start coverage from 10.30pm on Saturday night while the preliminary card will also be aired from 1am. The main card and McGregor fight will only be available on BT Sport Box Office, starting at 1am. It will cost viewers €29.95.
How important is the fight?
It's huge for both men.
McGregor's surprise loss to Poirier at UFC 257 in January means they have one victory each.
There is no title riding on the trilogy bout but the winner will likely get a lightweight title fight against current champion Charles Oliveira.
Poirier was first to officially weigh-in on Friday in Las Vegas and seemed in more of a relaxed mood than an intensely-focused McGregor, who aimed a kick at his rival at the end of a heated press conference 24 hours earlier.
There has been a distinctly edgier build-up to the rubber bout than their January rematch, where the relations were cordial, even friendly, ahead of an encounter in Abu Dhabi where Poirier levelled the rivalry at one win apiece.
On Thursday, McGregor, who won their first fight in September 2014 when the duo were up and coming featherweights, insisted his setback at the start of the year was “a fluke” as he looks to get back to winning ways.
McGregor compared his foe to former heavyweight boxer Buster Douglas, who defied his status as a heavy underdog to defeat then world champion Mike Tyson in February 1990 in one of sport’s greatest upsets.
“He’s Buster Douglas, he’s going to be known for that,” McGregor said at the final press conference. “It was a fluke win and I’m going to correct it on Saturday night.
“This is my bread and butter, this is what wakes me up with fire in my belly – errors to correct, tactics to prepare for. I’ve had a great camp.
“I’m going to go through his head, put holes in them and take it off its shoulders. He’s done here, this is it for him, this is the end of the road. Saturday night he’s getting walked around that octagon and put to sleep.”
Poirier admitted that McGregor “got into my head” before their first fight and the Dubliner seemed to attempt to get a rise out of the American by throwing his signature Louisiana style hot sauce into the crowd on Thursday.
On more than occasion, McGregor referenced Poirier’s wife Jolie, chanting “Jolie’s wife” and saying “your wife is your husband”. Poirier, who holds a record of 27 wins, six defeats and one no-contest in MMA, did not rise to the bait.
“The aura is not there any more,” Poirier said. “He’s a very dangerous fighter, no doubt, but I see a man here in front of me that I’ve defeated and I know I can defeat again.
“It’s just business, I see a man here. I don’t hate anybody, I’m in a different place mentally. Respect to him and everything he’s done.”
Former lightweight champion Rafael dos Anjos is on hand as a replacement in case anything befalls either of the pair ahead of this weekend’s headliner and the Brazilian-American also came in at 156lbs.