This match, the third in their trilogy, will be fought at 155 pounds (their first match in 2014 was fought at 145) in five rounds and the main event for the night. It's the same arrangement the welterweights had in their second fight. McGregor tweeted about it April 3rd, posting a photo of himself and saying, in part, that "you’re gonna see what the Mac is about."
Here's more from ESPN:
McGregor, sources say, had verbally agreed to the fight weeks ago. He made it clear following his loss to Poirier earlier this year that he wanted to run it back with Poirier right away.
Poirier defeated McGregor in January via second-round TKO in a rematch of a 2014 fight. Back then, at UFC 178, McGregor defeated Poirier via first-round TKO.
McGregor's loss in their second fight had to have been more galling than usual as Poirier flattened him at one point, inspiring Twitter memes about sleepy Conor.
Either way, the UFC will clean up. As ESPN notes, the Poirier-McGregor trilogy will ultimately "be one of the most lucrative in UFC history."
The location of the event is up in the air at the moment, but the UFC does plan to open it up for fans to attend. Fighters step into the octagon again on July 10, 2021.