Fallon welcomed a cavalcade of stars for his debut -- including former New York Mayor Rudy Giuliani, Lady Gaga, Tina Fey and Kim Kardashian -- but it was his first official guest, Will Smith, who joined him for "The Evolution of Hip-Hop Dancing."
Much like its previous incarnation, the hilarious "Evolution of Mom Dancing" with Michelle Obama, Fallon's latest bit took viewers on a journey through decades of popular dance crazes, from "The Running Man" to "The Dougie." Smith even performed a style made famous by his onscreen cousin, Carlton Banks.
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