Steven Seagal knocked a man unconscious when he was a martial arts instructor because he failed to realize his challenger was drunk.
The star is a black belt in aikido and became the first foreigner to operate a dojo training center in Japan after moving to the country as a teenager.
Seagal reveals locals were intrigued by his status and tough guys often challenged him to fights - but one encounter went badly wrong.
He says, "For the first couple of years people did come from all over Japan to challenge me. When they would show up when I was in the middle of teaching a class I'd be as violent and ruthless as I could be.
"There was one time, this guy says, 'I'd like to sign up for a duel to the death with you', and for an instant I thought, 'F**k me man, this is the guy... I'm gonna kill him' and I attacked. I was in the f**king air flying and I got closer to him and I realised he was just a f**king drunk.
"I'm already committed and I'm trying to put the brakes on from hitting him but he was in the air, out the door and tumbling for 20 feet and then he's unconscious and my wife thinks I did kill him and she's screaming, 'You killed him, you killed him!'"