The most heart-warming moment of Jimmy Fallon’s unprecedented performance Sunday at the Orpheum Theatre came when the late-night king slid up next to Justin Timberlake to re-enact their Bee Gees impressions in a giddy rendition of “Nights on Broadway.”

Unfortunately, the impromptu nod to their “Barry Gibb Talk Show” skits on “Saturday Night Live” came after the cameras were turned off, the Teleprompter wente dark and the 300-plus crew members began loading up the trucks for the long haul back to New York City.

Not that millions of viewers who stayed up late on a school night didn’t get enough treats during the live broadcast of “The Tonight Show,” 90 minutes after Super Bowl coverage had wrapped.

Dwayne Johnson munched popcorn while debuting a trailer for his upcoming film “Skyscraper,” which looks like the Rock’s version of “Die Hard.” Cast members from “This Is Us” stumbled through the drama’s “Big Three” chant. The Roots, the show’s invaluable house band, were in a jubilant mood after the Super Bowl win for their hometown of Philadelphia. And Timberlake showed off more musical chops than he did at halftime with the help of a fellow guest, country star Chris Stapleton.

After the show ended, the Orpheum audience started chanting "One more song!" Timberlake and his band obliged, singing "Drink You Away." 

Despite the sold-out venue’s lack of booze — or even diet sodas — the tightly-packed house had a party atmosphere, led by late-night’s most carefree host, who seemed genuinely giddy about his virgin voyage to the Twin Cities.

“You heard it here first. We are moving the show to Minneapolis,” he said at the top of the program as the crowd remained on its feet throughout his opening monologue. “Hold on to your tater tots!”

During a commercial break, Fallon took questions from the audience, triggering the inevitable request from one bold audience member for the name of his hotel.

“I’ll send you my room key!” Fallon replied.

His fans seemed delighted even though many had to wait in the subzero cold for more than an hour and no one was allowed to go to the rest rooms once they got to their seats.But if the event had a loosey-goosey feel, it’s only because those behind the scenes put in the time and energy to make it look that way.

Preparations started a week earlier, with a convoy that included four trailers of lighting gear and three of audio equipment. “The Tonight Show” regularly tapes in a studio with about 220 seats; the Orpheum crowd was 10 times that size, making it the biggest show since Fallon became host nearly four years ago. He’s remained No. 1 in overall late-night viewership for most of that time.

Fallon made time to play tourist, biting into a Juicy Lucy at the 5-8 Club and trading barbs with the surly staff at Mickey’s Diner. He also found time to do an interview at the KARE-11 warming tent, open for Kevin Hart at Target Center and sample Minnesota dishes at a Champlin family’s home in a bit for Facebook.

But he dedicated most of his three days in the Twin Cities to rehearsing at the Orpheum, a venue he chose, in large part, because it was once owned by his musical hero, Bob Dylan.

His impression of the Minnesota icon, a highlight of Sunday’s broadcast, was actually taped Saturday afternoon with numerous run-throughs. After each stab, Fallon was the first to suggest they try it again.

“Thirty more takes, guys, and we’re halfway there!” he joked at one point.

After he was finally convinced they had nailed it, Fallon relaxed a tad with writer/producer Mike DiCenzo, who had been instrumental in writing lyrics for an updated version of “The Times They Are A-Changin’.”

While Dylan has never appeared on the current version of “The Tonight Show,” Fallon told me he had come close to getting him twice. Once was for a bit in which they would sit together on a roller coaster and listen to new tracks. Another time he planned to introduce a Dylan cover band, only to discover that Dylan himself was leading the musicians.

I mentioned that Stephen Colbert had done a similar bit with Paul Simon during his first week as host of CBS’s “Late Show.”

Fallon looked at DiCenzo. “Well, I guess we can’t do that now.”

Fallon said Saturday he would most likely have a little case of the butterflies before the curtains rose the next night. But he always does. Overall, he was convinced the show would go without a hitch — even if the screaming baby that almost disrupted the Dylan taping were to make a return appearance.

“We also have a camel and a guy in an Abe Lincoln suit,” he said. “We’re ready for anything.”

Even, it turned out, a Bee Gees reunion.