Mike Tyson revealed heartbreaking reason he didn't know he was filming cameo for The Hangover

As we all remember, Mike Tyson put on quite the punchy performance in The Hangover, as it's really quite hard to forget him sparking Zach Galifianakis clean out in that hilarious scene.

But it turns out that we all nearly missed out on seeing the heavyweight legend, 58, render the comedian unconscious while singing along to Phil Collins' In The Air Tonight, as he completely forgot he was filming the hit movie.

He only realised he was due on set the night before - so instead of Tyson pouring over his lines and perfecting his stunts for weeks in advance, it seems like he was winging it.

The boxing champ still managed to put on a great show either way, but the reason behind the 2009 film slipping his mind is because he was struggling with substance abuse at the time.

Speaking to Tony Robbins in 2020, Tyson revealed he was drinking and using drugs a lot at the time, and only became aware of his role in The Hangover by pure chance when he was out clubbing the night before he was supposed to shoot.

He explained that he bumped into his co-stars in the VIP section and was left quite confused by this, as that was where he 'normally' sat, adding: "Nobody's normally here."

"So I went in there, I'm checking these guys to see what they're doing in my section," Tyson explained. "It was Zach, the other guy, and he said, 'We're going to be in a movie with you'.

Mike Tyson revealed he had no idea he was making a cameo in The Hangover until the night before shooting it (Warner Bros)

Tyson continued: "And I said, 'Yeah? When?', and he said, 'Tomorrow'.'"

If being informed you're meant to be part of an iconic film franchise like The Hangover while you're still out on the town doesn't sober you up, I don't know what will.

Tyson explained: "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."

It's a good job he was cast as himself, in hindsight.

Iron Mike also previously discussed how his alcohol and drug use persisted throughout production of the side-splitting film, telling Yahoo! Sports in 2012 that he was 'a mess'.

The boxer explained he was struggling with drug and alcohol abuse during production of the 2009 comedy (Kevin Winter/Getty Images)

He said: "I was overweight. I was a pig, high on cocaine. They had to know I was messed up. I couldn't talk. I had the cocaine talk."

Tyson has been sober for several years now, instead taking up smoking weed and starting his own cannabis line.

He reckons he should have done this throughout his 'whole career', as it 'puts him in this different state of mind'.

"I'm very relaxed and the more relaxed you are, the better fighter you are at least in my case," he added.

Let's hope he's feeling very cool, calm and collected when he takes on YouTuber Jake Paul in November then, and if we're lucky, we might even get to see a KO similar to the one he gave Galifianakis in The Hangover.