Everybody's nervous the first time.

But not everybody does it for the first time in front of a studio audience and millions of people. "We've never performed any song live -- ever," Akiva Schaffer said about the [artist id="3135075"]Lonely Island[/artist] crew making their live-performance debut Tuesday night on "Late Night With Jimmy Fallon."

"Andy [Samberg] did 'D--- in a Box' with Justin at Madison Square Garden, but we've never done a club show, not even a friend's wedding." The longtime friends and writing partners -- fresh off yet another viral-video triumph with the [article id="1611014"]Timberlake-assisted "Motherlover" clip[/article] from the most recent "Saturday Night Live" -- will appear on the show in support of their recent debut album, Incredibad.

The trio, which also includes Jorma Taccone, rehearsed the song they will perform with Fallon's house band, the Roots, on Monday and while Schaffer said it was nerve-racking, having the sickly talented hip-hop crew backing them up made it a bit easier. "Having your first ever live performance on national TV seems a bit misguided, but it went fine," Schaffer said.

"So many professional musicians sound so weird on talk shows, but we should be A-OK. Playing with the Roots, that's my dream. If the me of 10 years ago would know that I could perform a song with the Roots, I would lose my mind." While Schaffer preferred to keep the song choice a secret, he promised that in the hands of the Roots the raunchy tune sounds way different and, of course, way cooler.

The group will be joined by Roots rapper Black Thought on the song, after which only Samberg will take to the couch to talk up his upcoming hosting gig at the MTV Movie Awards and Sunday night's prime time "SNL" clip program, which will feature some of the show's most popular short films, from "D--- in a Box" to "Deep Thoughts" and the classic "Mr. Bill" bits.

It's actually the second time the Lonely Island have visited old "SNL" pal Fallon. The trio stopped by on February 11 to plug Incredibad and things went horribly wrong. Sitting in Fallon's office, the awkward interview began with Schaffer walking out almost immediately, while Taccone and Samberg did nothing but play the NBC "bing bing bong" theme song over and over on a knick-knack Fallon got from NBC as a Christmas gift, refusing to answer his questions.

As for a potential Lonely Island tour this summer, Schaffer said the group would love to hit the road, if they can get their schedules figured out. "Everyone's got random movie commitments, so if anything comes up one of us might not be able to do it," he said. "But we'd love to figure something out."