During his recent UFC 194 media scrum, interim UFC Featherweight Champion Conor McGregor went into detail about how his sparring session with “The Mountain” from “Game Of Thrones” came about.

As McGregor told members of the MMA media at a media lunch event promoting his massive title unification bout with Jose Aldo at this Saturday’s UFC 194, the sparring session with 6’9”, 400-pound actor Hafthor Julius Bjornsson wasn’t actually planned at all, and was completely spur of the moment.

McGregor explained how he had only asked Bjornsson to take a photo of the two squaring off, thinking it would be a cool picture due to the extreme size difference, when the two started bouncing around. From there, we all saw what happened when the video went viral.

“[I said,] ‘Let’s take a cool picture like that,'” said McGregor at the UFC 194 media event. “We squared off as if we were gonna do it. Then all of a sudden, he’s bouncing and I’m bouncing. Next thing you know, we’re having a full, bareknuckle body shot fight.”

McGregor continued, “I was hitting him with some shots. I had to hit him with some shots. He was trying to hit me as well. He wasn’t taking it easy. He tried to grab me and tried to pull my head off. I defended, freed the head. I was like this motherf*cker is so big, I have to start smashing him to the body.”

‘The Notorious’ one concluded, “It was a lot of fun. That’s a big man — 6-foot-9, 400 pounds. And I still folded him up.”