"Welcome, everybody, to Late Night With Jimmy Fallon. I'm your host, Dada," he playfully quipped.
"I'm emotionally drained. I'm a father of a beautiful baby girl, she's so cute. Her name is Winnie Rose Fallon, and she's so cute. She's 5 pounds, 9 ounces," he added, before squeezing in a few zingers. "I got down to the ounce—that's how I weigh myself as well. I've gotta lose a couple of ounces."
Fallon, who'll be taking over as host of The Tonight Show next year after Jay Leno steps down, went on to thank friends and fans for their well-wishes and described the experience as "crazy."
"It feels like it's been a four-day conference or something," he said. "It's very taxing on the fathers. I don't know how it is for the mothers, but very taxing."
This is the first child for Fallon, 38, and Juvonen, 46, who tied the knot in 2007 after meeting through mutual friend Drew Barrymore, who is a partner with Juvonen at production company Flower Films. (The duo produced, among many projects, Charlie's Angels and 50 First Dates.)
And, in case you're wondering, the royally serendipitous timing of his daughter's birth wasn't lost of Fallon, who couldn't help but crack about it.
"Yes, William and Kate will definitely set up a playdate—stop bothering me!" he sniffed. "I saw the invitation on the easel, yes!"