Conan O'Brien took a trip down memory lane in his return to late-night TV, telling Jimmy Fallon it felt "weird" coming back to the NBC building and joking about how Kelly Clarkson hijacked his studio.
The former host showed up Tuesday as a guest on "The Tonight Show," sitting down with Jimmy for an interview in which the comedian mostly reminisced about his time at the network.
At one point, Conan started talking about how strange it was to be back on "this floor" after hosting "Late Night" from 1993 to 2009 at NYC's Rockefeller Center. He then took the reins of "The Tonight Show" in L.A. before he was fired after just 7 months in 2010.
He said he was flooded with memories as he walked the hallways inside Manhattan's NBC headquarters. After that, he struck a few comedic notes.
Conan told Jimmy that he will experience the same feelings when he turns 98 and finally moves on from being host "and someone else will be in this studio."
Then Conan gave an example, namely Kelly Clarkson, who has her own daytime TV show that films in O'Brien's old studio.
Conan joked, "I love Kelly Clarkson. Who doesn't love Kelly Clarkson? But still, I felt like, 'It’s not right! Blasphemy! They should’ve burned it to the ground. And then Kelly came out to say hi. And I said, 'Don't talk to me. You make me sick!'"
Jimmy and everyone in the crowd laughed their butts off, highlighting the funniest moment of Conan's appearance.
Earlier in the day ... TMZ caught up with Conan before his 'Tonight Show' redux. He told us he was very excited to go back to the show -- insisting there was no bad blood between him and NBC brass. All's well that ends well.