UFC superstar Conor McGregor just went off ... blasting people who claimed he was insulting his Irish heritage by wearing a poppy on his shirt -- telling his critics, "F**k you and the Queen."
FYI -- the poppy is traditionally worn in British Commonwealth nations around Remembrance Day (November 11th) to honor soldiers who died in combat.
But in Ireland, wearing the poppy is controversial ... with some saying it represents the oppression by the British Army after World War One, the Black and Tans and the occupation of Northern Ireland.
Recently, an image of McGregor wearing a poppy began to circulate on social media ... with critics ripping him as a "sellout" and disrespectful.
So, moments ago ... Conor finally responded in a passionate Facebook entry:
"I know where my allegiance lies and what I do for my country. I don't need a stupid little flower with a 100 different meanings to tell me if I do or do not represent my country."
"Check the facts of its original meaning. ALL soldiers. ALL wars. I have the blood of many nations on my gloves. Fought and beat on the world stage. You have a pint in your hand and a Celtic jersey on in your local. F*ck you and the Queen."