Conor McGregor Visits White House, Unloads on Irish Government

It's officially a St. Patrick's Day party at the White House ... Conor McGregor's arrived!!

The UFC superstar -- and arguably Ireland's most famous native -- hit up 1600 Pennsylvania Ave. on Monday morning to celebrate his nation's big day ... and Donald Trump and Co. welcomed him with open arms.

The 36-year-old fighter fielded some questions from media inside the building's press briefing room ... before he filmed a fun video that White House officials threw up on their X page.

It wasn't all fun and games, though ... as Conor took aim at the Irish government over a number of issues while at the podium

"What is going on in Ireland is a travesty," Conor said. "Our government is the government of zero action with zero accountability."

Conor, of course, rocked green for the occasion ... pulling out a three-piece suit that paid some serious homage to the holiday. He buzzed his head and shaved his signature beard for the trip, too.

No images of McGregor and Trump have surfaced just yet ... but we're sure it'll be a love affair whenever they do come face-to-face -- as Trump just called him his favorite Irishman last week.

"He's got the best tattoos I've ever seen!" the president said.