In 2010, Tyson said he had agreed to play a caricature of himself in the Todd Phillips-directed film to fund his drug habit.
"I was a mess. I was overweight. I was a pig, high on cocaine," said the 46-year-old.
Tyson reiterated he only signed on to the project to "supply his drug habit", reported Daily Mail.
In the 2009 movie, Tyson threatens to harm the Wolfpack unless they return his stolen tiger, but in real life the cast inspired him to change his lifestyle.
"They had to know I was messed up. I couldn't talk. I had the cocaine talk," Tyson said of Ed Helms, Bradley Cooper, Zach Galifianakis, and Justin Bartha.
"So those guys are just beautiful people. They had my back, and I appreciate that and stuff, then they asked me to come back (in The Hangover 2)," he said.
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The boxer also spoke about his unexpected love triangle with ex-wife Robin Givens and pre-famous Brad Pitt in 1989.
Givens and Tyson had a famously short-lived marriage in the 1980s that was marked by violence.