It was a throwback evening on NBC since Paul Shaffer and longtime members of his backing band filled in for the Roots as they prepped for the SNL 50th concert

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,

On Feb. 10, David Letterman stopped by “The Tonight Show Starring Jimmy Fallon” while his former bandleader, Paul Shaffer, and his World’s Most Dangerous Band filled in for the Roots. It marked Letterman’s first “Tonight Show” appearance since Johnny Carson was host, back when the program still taped in Los Angeles.

He told Fallon: "I used to do a show just like this... We didn't do the Chuck E. Cheese crap." David Letterman Returns to The Tonight Show to Mostly Mock Jimmy Fallon

By David Letterman — with help from some flour tortillas — made a return to the late night stage Monday. “Paul and I used to do a show pretty much exactly like this,” Letterman noted to the Tonight Show audience.