WATCH: The famous Billy Crystal 15 Rounds roast of Muhammad Ali you should check out

Comedian was one of the eulogists at the three-time champ's memorial

Billy Crystal was among the eulogists Friday at Muhammad Ali's memorial service.

The friendship between the two started after a young Crystal did his "15 Rounds" roast of Ali back in 1979, where he broke out his impeccable Ali and Howard Cosell impersonations, to the delight of the champ.

Watch the memorial service live and get updates in our live blog.

Billy Crystal famously roasted Muhammad Ali in 1979. Screen Shot/@John D'Ark