The time that Prince showed up to perform on “The Tonight Show” without a guitar. The time a nervous Barbra Streisand hit her nose on the microphone stand in rehearsal. The time Jimmy Fallon convinced the Roots to become his house band by turning them into a human pyramid on a football field at UCLA.

Those were among the stories that emerged Wednesday night at the Paley Center for Media in New York when Fallon and Roots members Ahmir “Questlove” Thompson and Tariq “Black Thought” Trotter gathered with “Tonight Show” director Dave Diomedi to talk about favorite musical moments from the show.

Here are seven fun facts that emerged from the spirited conversation:

1. The “hey, hey, hey, hey” theme song for Fallon’s “Tonight Show” was rooted in the very first bumper music (the bits played leading in and out of commercials) the Roots wrote when their partnership with Fallon began in 2009 on NBC’s “Late Night with Jimmy Fallon.” Drummer Questlove was surprised when Fallon picked that tune out of a long list of potential theme song options as he prepared to take over “Tonight Show” in February 2014.

2. Fallon, Questlove and Trotter had a good chuckle at the memory of the time Prince stopped by “Late Night” to perform but his guitar tech forgot to actually bring his ax. Prince wound up borrowing a “beautiful” white Epiphone from Roots’ guitarist Captain Kirk Douglas. After a great performance, Prince “throws the guitar up to the crowd but there’s no one to catch it,” Fallon recalled. “It broke in half.” As Douglas watched in horror, Prince disappeared “in a puff of purple smoke,” Fallon said. “The next day we asked the camera crew for every angle on Kirk’s face” as the guitar flew up into the air, Questlove recalled. In the end, Prince made good and paid for the damaged guitar.

3. Trotter cited Bruce Springsteen and the E Street Band’s first appearance on Fallon’s “Tonight Show” as one of his favorite musical moments so far. The Boss told Fallon he intended to invite the entire studio audience down to the floor for dance party during his set. Fallon dutifully asked NBC security if that would be OK. When he was told absolutely not, Fallon said “can we pretend I never asked?” Springsteen did it anyway, to Fallon’s delight. “That’s our show — it’s so much fun. It’s electric. It’s a block party,” he said.

4. Barbra Streisand and Patti LuPone are among the legendary belters who “melted the room” with their performances, Fallon said. Streisand was incredibly nervous during her rehearsal, which surprised Fallon. She conked her nose on the microphone while blocking her appearance.

5. Director Diomedi works at warp speed to get each episode of “Tonight Show” in the can with minimal editing after the fact. “Dave does it in his brain — there’s not much editing,” Fallon said. The others joked about how quickly Diomedi leaves the studio once the taping is done. “I got a train to catch,” Diomedi said.

6. “Tonight Show” executive producer Lorne Michaels exerted some influence on the lineup of the Roots by decreeing that the band needed a bigger horn section to properly service Fallon as he took “Tonight Show” throne. “A king needs to be announced” was Michaels’ explanation, according to Questlove.

7. Fallon personally wooed the Roots to be his house band on “Late Night” by pitching them after they did a show at UCLA. Questlove took the meeting in the hopes of establishing a relationship that would help them with promotional appearances in the future, but he had no intention of taking the TV gig. At that time, the Roots had been living and working together for nearly 20 years and had become a kind of “hip-hop Grateful Dead,” Questlove recalled. Moreover, they were just starting to make a good living from record sales and touring. But Questlove knew something was up when he saw Fallon organize the rest of the band members into a human pyramid on a UCLA football field. “We’re not getting rid of this guy, are we?” Questlove recalled telling the band’s manager at the time. “He literally managed to disarm us.”

(Pictured: Ahmir “Questlove” Thompson and Tariq “Black Thought” Trotter)