NO!!!!
Will Smith didn't juice, he just eat a ton.
If you look at him, he's bulky not ripped. What I mean is he really didn't get any more muscle mass as he was already kind of built, he just put on some fat. Ali's body type was not ripped, but just big and bulky. That's all Will did was eat some fat shit and workout heavy with very little cardio...I read this in an interview, but for the life of me can't remember where