The late-night comedians also checked in on each other during their opening monologue.
It was a sight to behold as Fallon strolled onto the set of Jimmy Kimmel Live in Hollywood, California, and introduced himself simply as Jimmy after the boisterous crowd gave him a rousing ovation.
"I’ve switched places with Jimmy Kimmel, although as far as surprises you’ve seen on ABC this week, this one’s a distant second," quipped Fallon referring to Will Smith slapping Chris Rock at the Oscars last Sunday. Fallon added, "It’s really strange for me to be here. I feel like someone opened the late-night multi-verse!"
Over in New York City, Kimmel helmed The Tonight Show Starring Jimmy Fallon at 30 Rockefeller Plaza, where the L.A. host asked the audience to raise their hands if they were disappointed to see a different Jimmy hosting the NBC show.
During his opening monologue, Kimmel also joked about Smith's Oscar slap and prefaced the story by telling the audience about a crazy story that happened in L.A. last week. The crowd laughed before Kimmel interjected, "Are you figuring out what’s happening now? You’re noticing what day it is? Or no, maybe, I don’t know, April Fools' everybody!"
He later asked the audience, "Show of hands, how many of you are disappointed, be honest. OK, how many are very disappointed, be honest. And how many of you are thinking, ‘Oh my god, Jimmy Fallon looks terrible. I hope he isn’t sick.' We pulled the old switcheroo."
It's safe to say both audiences loved the hilarious prank, which Fallon revealed had been two years in the making but had to be put on hold due to the coronavirus pandemic. Kimmel said the operation was so top secret, not even The Roots, Fallon's house band, knew about the prank until the day it all unfolded. The late-night hosts later checked in on each other live.
Fallon interviewed Justin Timberlake, who spray painted "I [heart] Matt Damon" on Kimmel's desk. They also took part in Kimmel's popular "Celebrity Mean Tweets" segment but with a softer twist -- reading "Sweet Tweets" about each other.
Kimmel interviewed Hugh Jackman, and the duo took part in a Tonight Show game staple "Box of Lies." The Red Hot Chili Peppers, which was recently honored with a star on the Hollywood Walk of Fame and just dropped their 12th studio album, Unlimited Love, served as the musical guests for both shows.