UFC stars Conor McGregor and Dustin Poirier appeared to get into a war of words on social media over the weekend over the fallout from their latest fight.

Poirier reacted to McGregor’s prediction for their upcoming fight to end the rivalry. He accused McGregor of stiffing him on a donation to his charity after their fight in January. The two agreed that whoever won the fight would give some money to the other's charity of their choice.

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"That's a fun prediction! @TheNotoriousMMA you also predicted a donation to my foundation and you and your team stopped responding after the fight in January. See you soon. July 10th Paid In Full!" Poirier tweeted.

McGregor then responded: "A donation, not a debt. We’ve been awaiting the plans for the money that never came. I do with all my donations. Know where it’s going dot for dot. Otherwise it goes walking. As is the case with a lot of these foundations, sadly. You took the McG over the belt shows I was right."

FLASHBACK: DUSTIN POIRIER SHOCKS CONOR MCGREGOR AT UFC 257

Poirier said the Irishman’s team didn’t respond to their emails.

"100% never a debt. You offered, we accepted, and like I said your Team never responded to our emails regarding the process of where funds would be put to work! July 10th you will taste defeat yet Again," he said.

McGregor fired back and got expletive.

"My team does their due diligence to make sure every donation meets the mark. My generosity is known. You will pay with your brain for this attempt at smearing my name. Shooting a*s shelling a*s b---h. Little b---h kicks from a shell. Good luck when you’re caught. You’re f—ked."

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McGregor and Poirier were set to fight at UFC 264, but McGregor tweeted the fight was off over the money.

Poirier knocked out McGregor during their last bout.