Behind the scenes of Jimmy Kimmel and Jimmy Fallon's swapping shows: Kimmel first pitched the idea to Fallon four years ago

The Hollywood Reporter

The Jimmys tell The Hollywood Reporter that to pull off their epic Tonight Show-Jimmy Kimmel Live! April Fool's Day prank, only a small number of producers, writers and network executives were in the know. Both hosts taped two episodes on Wednesday, so Fallon could work with Kimmel at his show in Los Angeles on Thursday -- before Kimmel flew out to New York City. It took "tons of planning. Tons," says Fallon. "And to keep it a secret. Our producers were talking to each other every day for the past month. But this probably took a year of planning." Kimmel added: "We prepared more for this show than most. What was most important was looking out for the other, sharing the little tricks you pick up over the years."