If there ever was a person who didn't rap but had a rap name it was Chill Wills . The actor/singer's moniker drips hip-hop. Hell, he even had a PR man nicknamed "Bow Wow," and, supposedly the publicity campaign for his 1960 Best Supporting Actor Oscar nomination went so hard, it pissed off co-star John Wayne. Going way overboard telling everybody how ill you are? Yeah, that's definitely some rap shit.
However, had Will.He.Be been a rapper, perhaps he might not have been any good, as suggested by the title of one of his movies, Francis Joins the WACS . (Although his singing group, the Avalon Boys, does sound vaguely like a crew on some current hipster shit.) Still, there's no denying the ice cold prestige of the Chill Wills' name.
(Props to @grandgroove for the suggestion. Thanks for your patience.)