The new episode kicked off with Fallon filming as the couple's two daughters, Winnie and Frances, surprised their mother with a cake and performance of "Happy Birthday."
"Trouble," Nancy remarked at Jimmy when she saw what he had done. She then told the girls, "I love you so much" before blowing out the candles.
"It's a special day here because it's my wife's birthday," Fallon said next, as he moved on to his opening monologue. "The producer, camera operator, location scouter, editor. We love you honey. I know you don't like dramatic surprises."
After presenting her with some fancy olives from his father, Fallon then revealed the best gift she got came from friend Liza Burnett Fefferman, Executive Vice President, Communications Entertainment & Youth Brands at ViacomCBS.
Explaining that "The Challenge" is one of their favorite shows, Fallon explained how Liza's MTV connections came through -- with a personalized video from Johnny Bananas.
"This is a very special happy birthday shoutout going out to my girl Nancy, coming to you from your boy Johnny Bananas," he says in the video. "Nancy, may you live, may you love and may your birthday in quarantine be absolutely bananas."
"I could not even teach today," said Nancy, as Jimmy said she was "so geeked out" about the b-day message. Calling it an "untopable gift," Fallon hoped it meant they were in store for another "bananas year."