The boxing icons both appeared on the same talk show alongside another great Sugar Ray Leonard.
Tyson and Ali ran into each other in 1989 on an episode of the Bill Arsenio Show.
Ali was eight years retired at that point after his 1981 loss to Trevor Berbick.
Tyson, meanwhile, was the unbeaten, unified world heavyweight champion and tearing through the division.
But his respect for Ali was clear to see on the show and vice versa.
Ali and Sugar Ray were already on the sofa when Tyson was introduced.
Iron Mike’s arrival seemed to put Ali on edge.
Host Arsenio asked the former champion wh at was wrong, to which Ali replied: “I’m scared of him”.
The host hit back: “You’re scared of this one? He’s a sweetheart.”
Ali said: “He’s a real champion.”
The host then got onto the million dollar question.
He asked Ali who would’ve won in a fight between the pair in their prime.
Without hesitation Ali pointed at Iron Mike, who looked a bit embarrassed by the praise.
Ali said: “I was a dancer boxer. I wasn’t that powerful, I was so fast. But if he hit me.”
And he ended his reply by pretending to be knocked out cold.
Tyson responded: “I know I’m great but can I tell you something.
“In this situation, every head must bow, every tongue must profess, this is the greatest of all time.”
His response received huge roars from the talk show crowd.
Ali said: “He can be modest, humble and nice but this man is great. And I don’t know what would happen if he hit me.”
Tyson then hit back: “I’ve seen him in the ring with killers. He takes these guys best punches and that’s what makes him a champion.
“From listening to Ali, that gave me belief that there was no man who could beat me.”