David Letterman Surprises Jimmy Fallon as Paul Shaffer Takes Over ‘The Tonight Show’

David Letterman made a surprise cameo on The Tonight Show Starring Jimmy Fallon on Feb. 10, interrupting Fallon’s monologue to welcome his longtime musical director Paul Shaffer and The World’s Most Dangerous Band, who are filling in for The Roots during their week of rehearsals for Saturday Night Live’s 50th-anniversary concert.

Fallon had wrapped up a joke about Super Bowl LIX when Letterman suddenly walked onto the stage, prompting Fallon to shout, “Oh, my God! David Letterman?! My God! What are you doing here?”

Letterman, unfazed, delivered a classic deadpan response: “Is this the 23rd hour of the Today show?” before turning his attention to Shaffer. “Paul?! What are you doing here?!”

Shaffer, who spent 33 years as Letterman’s bandleader on Late Night with David Letterman (1982-1993) and The Late Show with David Letterman (1993-2015), is stepping into his old late-night groove this week as The Tonight Show’s temporary house band leader.

“You know, it’s a funny story,” Shaffer joked. “You ever taken too much Ambien and then you wake up somewhere with no clue how the hell you got there?”

“Wow. You’ve been reading my diary,” Letterman quipped.

The impromptu reunion quickly escalated into full-on late-night chaos. After Fallon suggested making a Tiktok video together, Letterman joked, “I made an enormous deal with the Chinese government.” When Fallon proposed a “handshake challenge” for the viral moment, Letterman shot it down immediately. “Yeah, that was lame,” he declared. “What I really want to do is hit you in the face with a tortilla.”

That’s exactly what happened next. As the band played along, the two hosts engaged in an all-out tortilla slap battle, with Fallon laughing, “I think you cracked a crown!” Letterman didn’t let up: “We’ll see you in court.”

Shaffer and The World’s Most Dangerous Band will continue their Tonight Show residency through Feb. 14, bringing a throwback flavor to Studio 6B while The Roots prepare for SNL’s milestone special. With Letterman proving he’s always ready to crash a late-night set, the rest of the week could bring even more surprises.