The former 'SNL' cast member commemorated the big night with a massive lip sync performance involving the whole cast and even Harry Styles.
Jimmy Fallon returned to host Saturday Night Live for the first time since 2013 and the versatile star kicked off the night with a massive musical monologue.
After appearing as Ivanka Trump's husband, Jared Kushner, in a hilarious and (mostly) silent role in the cold open, Fallon took to the Studio 8H stage to open up SNL's first-ever live-on-both-coasts episode with an epic dance number involving dozens of back-up dancers.
"Tonight is bigger than just a show," Fallon said, as David Bowie's "Let's Dance" began to swell. "It's a party!"
Lip syncing like a pro, Fallon walked off stage and was followed by a studio audience (filled with professional back-up dancers) as they danced through the halls of the studio.
Joined by the entire cast of SNL singing and dancing along with him, Fallon also shared a fun lip sync duet with music guest Harry Styles, and their adorable comic chemistry was palpable.
Check out a few of Fallon's best sketches of the night below:
"Donald Trump Cold Open"
"Take Me Back"
"Celebrity Family Feud: Time Travel Edition"
"New Shirt"
"Sully & Denise"
Early Saturday morning, the former SNL cast member took to Instagram to commemorate his history with the long-running sketch comedy series, sharing a mirror selfie from his dressing room, with a cheeseburger and a shake on the table in front of him.
"In 1998 hours before I auditioned for Saturday Night Live - I got a cheeseburger and a banana health shake (ice cream, banana and wheat germ - really healthy) from Ellen's Stardust to go. I have it once a year for good luck. They now have my name on the menu," he wrote. "I'm so happy to be home and I hope you enjoy the show. #FallonStylesSNL"
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Recently, Fallon opened up to ET about hosting the show's first-ever truly live episode, and he said he was "honored" that they asked him to "be part of the [show's] history." Watch the video below to hear more.