Mike Tyson has just admitted that he was drunk and high while on the set of the hit movie The Hangover, which was released back in 2009.

The 54 year-old heavyweight champion said that he did not even know that he would be appearing in the film until he bumped into Zach Galifianakis and his fellow co-stars on a night out.

It was then that he was told about his cameo, which he filmed the next day.

“I met the guys in a club, they were in the VIP section and I said, ‘This is where I normally sit, nobody’s normally here,'” Tyson told motivational guru Tony Robbins.

“So I went in there, I’m checking these guys to see what they’re doing in my section. It was Zach, the other guy, and he said, ‘We’re going to be in a movie with you’ and I said, ‘Yeah? When?’ And he said, ‘Tomorrow,’” Tyson recalled.

“And I didn’t know as I was drinking and smoking back then, doing drugs so I didn’t know I was involved in the movie. So eventually I had to go and do the movie and it was a success.”

Tyson played himself in the movie, which featured Galifianakis, Ed Helms and Bradley Cooper stealing one of the boxer’s tigers.

Tyson eventually knocks out the character played by Galifianakis before his tiger cat is returned.

The New York Post reported that Tyson had previously admitted that he was high on cocaine while filming the movie.

“I was a mess. I was overweight. I was a pig, high on cocaine,” he said.

However, Tyson also credits his famous punch of Galifianakis’ character with helping him regain his popularity with his fans.

“One day I’m in a restaurant and the movie hadn’t come out yet, but the kids must have seen the preview of me punching Zach,” Tyson said.

“So one of those sightseeing buses went by and all the kids came off the bus and grabbed me, taking pictures and my friend says, ‘I think we’ve got something here, Mike’ and I said, ‘Yeah, me too.’”

“It’s been different, it’s changed ever since,” he added.

“When I go out and I meet younger kids that are 20 or 15, it’s because they watched ‘The Hangover’ — they had no idea that I used to be a boxer.”