We had to wonder: How many times did Jimmy Fallon and Justin Timberlake practice this rap medley? Or is most of it made up on the spot?

We had to wonder: How many times did Jimmy Fallon and Justin Timberlake practice this rap medley? Or is most of it made up on the spot?

Douglas Gorenstein/NBC
Ellen DeGeneres takes on a dramatic Diana Ross number while Jimmy Fallon and Justin Timberlake try not to giggle.

Ellen DeGeneres takes on a dramatic Diana Ross number while Jimmy Fallon and Justin Timberlake try not to giggle.

Douglas Gorenstein/NBC

Wednesday night was a big night on The Tonight Show Starring Jimmy Fallon. First, he kicked off the show with a rap medley with Justin Timberlake. Then he battled Ellen DeGeneres in a two-round lip-synch contest judged by Timberlake.

We couldn't help but think it was Fallon's moment to lure curious Stephen Colbert watchers back to NBC. (Colbert debuted in David Letterman's CBS spot one night earlier, on Tuesday.) So give Colbert a day, fine. Then on Wednesday, huge names like Timberlake, DeGeneres and musical guests Macklemore and Ryan Lewis were just too big to change the channel from NBC.

Fallon and Timberlake's "History of Rap 6" was a marathon of hip-hop numbers, chewed up and spit out in hilarious fashion. Fallon might've gotten a little winded. Not Timberlake. Watch:

Then Timberlake took a back seat while Fallon and DeGeneres battled in a semi-regular Tonight Show stunt, the lip-synch competition. 

The audience went nuts for DeGeneres' hilariously understated Diana Ross song, "Theme from Mahogany (Do You Know Where You're Going To)." 

I found Fallon's gangly "Watch Me (Whip/Nae Nae)" to be the best of the night. Or was it Ellen's "B*tch Better Have My Money"?

The only thing missing from that performance would have been a lip-synch from Timberlake. We would die if he took on a Backstreet Boys song.

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