The American lightweight tweeted simply "July 10th" and a diamond (his nickname) - a clear sign that this is the final date for the long-awaited fight.
A third contest against the Irishman - with the series tied at 1-1 - was originally scheduled for May, but has been pushed back so both parties could agree terms.
That will likely make McGregor vs Poirier III UFC 264 - and it will happen in the middle of International Fight Week, where the UFC host their Hall of Fame induction ceremony and other fan events. Ideal timing for a hotly anticipated contest.
Dana White is yet to officially confirm a venue for the contest, but he has strongly hinted that it will be the T-Mobile Arena in Las Vegas come July.
McGregor first took on Poirier in a featherweight contest in 2014 and stopped him inside two minutes. That made 'The Notorious' a strong favourite going into their rematch at lightweight in January.
However this time it was 'The Diamond' who shone, breaking down McGregor's resistance with powerful leg kicks and taking out the tiring Irish superstar in the second round.
That perfectly set up a third, deciding rubber match. And while the delay to 10 July wasn't part of the original plan, it is likely good news for McGregor.
The 32-year-old clearly needs to work on his strategy and MMA technique going into the third fight, amid accusations that he's become too reliant on his boxing style, while standing flat-footed in the Octagon rather than displaying his formerly fluid movement.
Poirier goes into this contest with the knowledge that he can outlast his opponent, but the 32-year-old from Louisiana will also be aware that McGregor can hurt him.
It's a fascinating set up and like we'll see who pulls clear in the rivalry on 10 July in Las Vegas.
All imagery: PA Images
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