Last night when Justin Timberlake was a guest on Late Night with Jimmy Fallon, we expected him to talk about his new movie about Facebook — The Social Network — and he did, but I don’t think anyone was expecting the hysterical “History of Rap” medley with host Jimmy Fallon!

JT and…JF…covered hip-hop favorites that span the last 30 years, including:

Sugarhill Gang‘s “Rapper’s Delight,” Beastie Boys‘ “Paul Revere,” Dr. Dre‘s “Nuthin’ But a ‘G’ Thang,” Digital Underground‘s “The Humpty Dance,” Eminem‘s “My Name Is,” Kanye West‘s “Gold Digger,” and Jay-Z‘s “Empire State of Mind,” and Missy Elliot‘s “Work It”

And of course, Late Night’s house band The Roots played musical accompaniment.

So much awesome! I wonder if they practiced it ahead of time?

In the interview, Justin briefly made mention of that “little group” he was in, ‘NSync, and recalled how Sugarhill Gang once opened for them– before launching into the breakdown of songs with Jimmy.

It was a good night for late-night television!

Justin’s new movie ‘The Social Network’, starring Jesse Eisenberg as Facebook creator Mark Zuckerberg, opens in theaters tomorrow.