Last night (Feb. 17), a massive roster of A-list stars kicked off Jimmy Fallon's debut as the new host of 'The Tonight Show.' However, it looks like they didn't believe the comedian could land the gig.

"I can't believe this is happening, I'm really sitting here," Jimmy told the audience. "I want to say thanks to all of the fans for their support and to my buddy, who said I'd never be the host of 'The Tonight Show' -- and you know who you are. You owe me 100 bucks, buddy."

He was cut off when Oscar-winning actor Robert De Niro walked out onstage and slapped a $100 bill down on Jimmy's desk. Before Jimmy could continue his monologue, a trail of other celebs -- including Tina Fey, Lindsay Lohan and Kim Kardashian -- reluctantly handed over their own dues.

Although the stars pretended to be bitter over paying up, Lady Gaga couldn't resist bending down and whispering "Congratulations!" into Jimmy's ear. Awww!

Watch all of the hilarity go down in the video above!