The actor is a family friend and portrayed the boxing icon in his 2001 biopic.
Over the course of more than 30 years, ET spent plenty of time with the champ, so we're looking back at some of our favorite memories with the late icon.
The late icon's twin daughters opened up to ET about the loss of their father and the impact he had on the world.
Mila Kunis and Ashton Kutcher Caught on Kiss Cam!
The rapper tested his power in New York on Monday morning when he hinted at a surprise concert, which caused a frenzy in the Big Apple.
There was one person who believed the actress would be a star even when her father didn't - Muhammad Ali.
'She came out and said, 'Oh, I'm not singing today.''
The rocker helped end the Broadway show with her legendary twirl.
It was real-life 'Hunger Games' in the Hemsworth household!
The model is getting in some natural healing as she battles Lyme disease.
The Bravo-lebrity has some Snapchat fun with ET!
The author shut down backlash over the casting of a black actress to play Hermione.
The 18-year-old is sporting a sexy look while filming her new movie.
The actress is ditching the glam and embracing her grays!
