The ex-heavyweight champion is currently training MMA man-mountain Francis Ngannou ahead of his controversial crossover clash with Tyson Fury on October 28.

However, it appears that one of their sessions was interrupted by another beast – and the icon known as the Baddest Man on the Planet was in his element.

It showed a group walking into the gym with a massive, that looks similar to a mastiff, on a lead, but instead of looking fearful, Tyson went straight on to embrace it.

After stroking it, Iron Mike then got down on his hands and knees before rubbing his head against the dog’s and then underneath it’s chin.

One fan reacted to the footage on social media by commenting: “Mikes a brave man… thats probably the worst thing u can do putting your face into a strange dog’s face. Good thing they a good boy!”

Another said: “Mike started challenging him and wanted to grapple lmaooo.”

“That dog was lucky Tyson didn’t punch him,” joked another.

Tyson is a renowned animal lover and previously kept three tigers as pets.

However, he has revealed that mountain lions are his favourite animals.

The American icon also revealed that he used to let his tigers sleep in his bed next to him – but that their farts were unbearable.

But he also admitted that he had suffered injuries from a big cat – and a dog.

He said: “I was giving one a tetanus shot and they bit me.

“It was scared, he was scared. Six, seven stitches and it was over.

“Then my dog bit me.”

Meanwhile, he is trying to get Ngannou, 37, in shape to do in ten rounds what 31 of the Gypsy King’s career opponents have failed to do and put him out for the count.

But Tyson insists: “He has what it takes to knock out anything and anybody.

“[The biggest upset] in the history of the sport, definitely. There’s no doubt about that.”