Conor McGregor just had his most epic face-off to date -- a shirtless staredown with Sir Richard Branson!!
It all went down at the Pendulum Summit for business leaders in Dublin, Ireland ... where Conor was presented with a lifetime achievement award for his BIG money moves.
Branson joined McGregor onstage -- and after some back-and-forth, convinced the UFC mega-star to bro out.
Waiting for your permission to load the Facebook Video.
Not to be outdone, Rich ripped off his top too ... and we gotta say, dude looks pretty frickin' jacked for a 67-year-old gazillionaire.
The whole thing was kinda weird -- but mostly awesome.