While you might be saying, “I know him,” it’s not from Broadway — Killam will be making his Great White Way debut in the hip-hop musical, though he is an experienced musical theater actor. And if you’re perplexed and wondering if they’re going to keep on replacing whoever’s in charge, the answer is yes: Killam will be the fifth actor to wear the crown, after Brian d’Arcy James, Jonathan Groff, Andrew Rannells, and O’Malley.