Jon Hamm and Jimmy Fallon photobomb tourists

Jimmy Fallon gave visitors to Rockefeller Center’s Top of the Rock in New York a souvenir worth bragging about when he and “Mad Men” star Jon Hamm photobombed their tourist snapshots.

During “The Tonight Show” Monday, the comedian said that his crew told sightseers that they were taking photos to be used for the Top of the Rock’s website.

“We were lying,” he deadpanned before cracking himself up as he explained the “Celebrity Photobomb” gag.

Behind the backs of the unsuspecting, the duo pulled off poses ranging from chowing down on a hoagie “Lady and the Tramp” style, to doing a Kriss Kross (“Jump!”) to chest bumping and more.

“Everyone’s going to be out there doing the hoagie-ing photobomb,” Fallon predicted afterward.

The antics had Kathie Lee Gifford and Hoda Kotb giggling on Tuesday during TODAY. “The genius of Jimmy (is) he can get pretty much anyone to do pretty much anything!” Gifford said.

“The Tonight Show” airs weeknights at 11:35 p.m. on NBC.