Justin Bieber Discovers He's 60% Irish and Conor McGregor Loves It

Justin Bieber better learn to love whiskey and potatoes ... 'cause he's Irish!!!

The Biebs ecstatically revealed Saturday he's around 60% Irish ... prompting him to give Ireland a shout-out on his Instagram story. This was in response to his pops, Jeremy, posting on IG showing him holding a bottle of Conor McGregor's Proper Twelve Irish whiskey.

Naturally, all of this got Conor's attention who jumped on Twitter and embraced his fellow deartháir -- don't look it up, it means brother.

Justin, of course, was born in Canada and not long ago had huge plans on applying to become an American citizen. The kid's literally taking over the world, eh?!

The Biebs' got good timing ... Conor sent his love all the way from Dublin where he was there taking part of an exhibition boxing match. Conor kicked ass ... and now he has 2 reasons to slam back a few Proper Twelve shots.