CONOR MCGREGOR'S Facebook account launched a stunning attack on Guinness in a series of furious posts.
The UFC fighter is not a fan of the famous Irish beverage, and created his rival Irish Forged Stout a few years ago.
He also opened a pub in Dublin selling the beer alongside his Proper 12 Whiskey.
And although both drinks have proved a success for McGregor, it seems he still feels a need to try and bring down the competition.
McGregor's Facebook account slammed Guinness and its founder Arthur Guinness on a community page dedicated to the famous stout.
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One post read: "Greedy robbing b******s.
"Arthur Guinness was a rat for a foreign entity. Today his corporation hikes up prices every second month out of pure greed.
"Ask any of the publicans where you drink. They all despise them. Forged Stout is the working man's drink!
"Real Stout. Real prices. See you all cageside, Arthur could never."
McGregor, 35, has sparked fears his fight with Michael Candler could be cancelled after he postponed a press conference.
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The duo are just over three weeks away from a Las Vegas clash in in the main event of UFC 303.
McGregor appears to have continued partying in recent weeks, though Dana White questioned the authenticity of videos that appeared online.
He said: "I don't know what's real on the internet and what's not real on the internet.
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"I don't know timing-wise. In one of them he's got a beard, in one of them he doesn't have a beard.
"I have no idea, I don’t know if any of that is real or true or whatever."
