"Dad, dad!" Fallon yells, after waking up in room that resembles Michelle Tanner's bedroom from the 1987 sitcom. Danny Tanner (Saget), Uncle Joey (Coulier) and Uncle Jesse (Stamos) then show up to comfort the host, who reveals he's scared about leaving Late Night to take over the Tonight Show.
"I guess I'll just miss the Late Night show. I've been doing this for five years," Fallon says. "There have been so many special moments and so many great musical guests."
"Jimmy, I know you'll miss the memories you made at Late Night, but now you can make new memories at the Tonight Show," Danny says. "And, just like Uncle Jesse said, you're going to be the host of the Tonight Show on NBC. Honey, nobody can take that away from you."
"Well, maybe Jay Leno," Uncle Jesse jokes.
"Haha, Jess, cut it out!" Uncle Joey quips.
The Full House trio then sing their version of the Elvis Presley song "Teddy Bear" to help lull Fallon back to sleep.
Watch the funny Full House reunion on Late Night in the video above.