Following McGregor's victory over Poirier in September 2014, 'The Diamond' exacted his vengeance earlier this year in spectacular fashion.
Poirier dominated McGregor with vicious leg kicks and punches to take the rematch and set up a tense third battle.
The two are set to fight again as the main event of UFC 264, although there has been some confusion about the fight after McGregor's spectacular expletive-laden outburst on social media to his opponent.
But UFC president Dana White has since announced that the clash will take place, and here's what we know so far...
Date and period for McGregor vs Poirier 3
The main show is set to take place on Saturday, July 10, at the T-Mobile Arena in Las Vegas, Nevada.
The start times have not yet been reported, but UK fans can anticipate the main event to begin about 6 a.m. on Sunday.
What has been mentioned about McGregor vs Poirier 3?
On Wednesday, April 14, Dana White announced the battle date in a video shared on Twitter.
“I am so grateful to actually be willing to say: Vegas is back,” he added.
“Las Vegas is back in operation this summer, and on July 10, UFC 264 will be at full peak at the T-Mobile Arena. That's 20,000 people, ladies and gentlemen.
“So the main event on this card will be the third battle between Dustin Poirier and Conor McGregor.”
Prior to White's declaration, the battle had been called off due to McGregor's rant.
'The Notorious' took to social media to respond to Poirier's latest allegations that the Irishman had failed to fulfill his promise to contribute $500,000 to his charity organization, the Good Fight Foundation.
“You're ripped, you inbred hillbilly,” he tweeted. Why can you have an ear wink? You f****** deafeningly deafeningly deafeningly deafeningly With no contingency in action, a $500k loan becomes a $500k loan. Hold on fast. Idiot.
“You've got to be new to money. By the way, the war has been called off. On the 10th, I'll be fighting someone else. Best of luck with your old contract kid.”
Poirier replied to McGregor on Twitter with the term "yes" and a GIF of the moment he knocked out his lightweight opponent in January.
McGregor replied with a gif of his own, followed by the reply "see you later pea," informing Poirier of his setback in the octagon when the two first met in September 2014.
McGregor then said, in response to Poirier's tweet regarding their donation conflict a day earlier, "My staff performs their due diligence to ensure any donation hits the target." My kindness is well-known.
“Good luck if you get trapped. You're f*****g f*****g f*****g f*****g f
“You would compensate for this effort to slander my reputation with your brain. Shelling butt b****ing ass b****ing ass b****ing ass b****ing ass Little b**** kicks out of the shell.”
McGregor vs Poirier 3: TV coverage and video streaming
UFC 264 Live Online would most definitely be a pay-per-view match in the United Kingdom, broadcast on BT Sport Box Office.
More information about how to watch the event will be released shortly.
McGregor vs Poirier 3: Fight card
More information will be provided when it becomes accessible.
Dustin Poirier v Conor McGregor - Lightweight
Gilbert Burns v Stephen Thompson - Welterweight
Tai Tuivasa v Greg Hardy - Heavyweight
Jessica Eye v Jennifer Maia - Women’s Flyweight
Ryan Hall v Ilia Topuria - Featherweight
Jerome Rivera v Zhalgas Zhumagulov - Flyweight
Omari Akhmedov v Brad Tavares - Middleweight