"To my buddy who said that I'd never be the host of The Tonight Show, and you know who you are, you owe me a hundred bucks," the new host joked. Moments later, Robert De Niro came out and handed Fallon a $100 dollar bill, followed by Tina Fey, Joe Namath, Rudy Giuliani, Mariah Carey, Joan Rivers, Kim Kardashian, Seth Rogen, Mike Tyson, Lady Gaga, Lindsay Lohan, Tracy Morgan and Sarah Jessica Parker.
Stephen Colbert walked out last and dumped a bucket of pennies onto both Fallon and his desk. After snapping a selfie with the former Late Night, Colbert shouted, "Welcome to 11:30, bitch!" Fallon, 39, then joked, "Thanks for believing in me, guys!" before cuing up the first commercial break.
"I just want to do well," Fallon told the audience during his opening monologue. "If you guys let me stick around long enough, maybe I'll get the hang of it." Will Smith served as his first guest.
Gaga, meanwhile, will return to The Tonight Show Tuesday as the featured musical guest; celebrity guests Ben Stiller and Kristen Wiig are also slated to appear on Fallon's late-night talk show that night.
(E! and The Tonight Show are both part of the NBCUniversal family.)