Tina Fey, Kim Kardashian, Lady Gaga, Stephen Colbert, And More Surprise Jimmy Fallon On 'Tonight Show' Debut

Jimmy Fallon hosted his first "Tonight Show" Monday out of his new studio in New York City and a few famous friends dropped by to send their regards.

But instead of congratulating the host, a steady stream of stars each came out to pay Fallon $100 after he said he has a friend who owes him $100 because the friend bet he'd never become the host of the talk show.

On cue, Robert De Niro walked onstage and gave Fallon $100. He was soon followed by Lady Gaga, Tina Fey, Mariah Carey, Rudy Guiliani, Kim Kardashian, Tracy Morgan, Joe Namath, Seth Rogen, Lindsay Lohan, Joan Rivers, Mike Tyson, Sarah Jessica Parker, and Stephen Colbert.

Watch the funny segment below:

Colbert stayed the longest on-stage with Fallon, dumping 1,000 pennies on his desk and saying, "Welcome to 11:30, b----!"

Kim Kardashian Instagrammed a behind-the-scenes photo from the star-studded show.

She wrote, "Mike Tyson, Sarah Jessica Parker, Tracy Morgan, Joan Rivers, Gaga, Lindsay Lohan backstage at Jimmy Fallon tonight!"