The 72-year-old promoter is impressed with how the Gypsy King has turned his life around after hitting rock bottom with his mental health.

He told Boxing News magazine: “What makes it so special is where Tyson came from.

“Having seen how he put all that weight on, boozing, substance abuse, the mental problems he was having that made him think about taking his own life.

“That’s the deepest depths of despair. I can say that, because my younger brother Mark did that – he committed suicide.

“To think you’re in so much pain that the only way you can rid that pain is to end your life, that’s some horrible place to be in.

“To see Tyson overcome his demons, which he has to fight on a daily basis still, and to fight as well as he does in the world’s toughest sport against some of the best heavyweights of the century, I’m really proud of what he’s done.”

Tyson is set to face Oleksandr Usyk later this month in a rematch following their bout in May, and Frank predicted he will pave the way for a third fight between them next year.

He said: “Irrespective of whoever wins that fight, he should be proud of even getting back in the ring at all.

“And, by the way, I think he wins the rematch – and then we will be able to set up the third fight, a trilogy match, in the new year.

“Can you imagine how big that will be?”