'Game of Thrones' star Nikolaj Coster-Waldau once walked in on George Clooney in the bathroom

Nikolaj Coster-Waldau might not play the most likable character on "Game of Thrones," but he is a sweet, funny guy in real life. The man known on the HBO fantasy series as Jaime Lannister got to show off his real self on "Conan," where he told a hilarious anecdote about his recent trip to the American Film Institute award luncheon.

"Every year there's a lunch where they pick out the 10 best movies, and this year as well 10 best television shows. We were there and it was really cool and it's a lunch, they serve you drinks and food and it was one of those places where whenever you put your glass down there's someone there to fill it up," Coster-Waldau says.

He continues, "At the end, I was just dying. I had to go to the restroom. Finally it's over and I'm just running out there and it's packed with people. All the urinals are [full] but then I spot there's a stall and the door's open. So I go, I'm not going to let anyone get there. I was dying. ... This idiot -- this guy -- was in there, so I just go for it. I didn't know, the door was open, I just go for it. There's a guy there, he's standing. I'm pretty sure there's spillage. I just ran into him. I said, 'Sorry,' and he said, 'Sorry,' and then I go, 'My god, that's George Clooney.' He's so short."

According to Coster-Waldau, this is actually a "cautionary tale." "Guys do that. Why? He's smart, he can win Oscars and he's a great director, but ... close the door or you leave it open," he says.

Watch the second part of the interview where Coster-Waldau talks about getting very, very muddy below. "Game of Thrones" airs Sundays on HBO at 9 p.m. ET.

Photo/Video credit: TBS