Conan O'Brien Zings Jay Leno Night of Host's Final 'Tonight Show' (Video)

Conan O'Brien
Joe Pugliese

O’Brien was photographed by Joe Pugliese on April 12 at the Avalon Hotel in Beverly Hills.

Conan O'Brien limited himself to one joke about Jay Leno Thursday, but as he says, he made it "a good one."

O'Brien, who famously was forced out of his job as Tonight Show host to make room for Leno in 2010, poked fun at the host's second Tonight departure.

VIDEO: Jay Leno's Final 'Tonight' Brings Billy Crystal, Oprah Winfrey and a Musical Tribute

"The Olympics start airing tonight on NBC. It's very cool. That's right, NBC has the Olympics. It's a big deal," O'Brien said in his opening monologue on TBS' Conan Thursday. "NBC will finally get to show somebody who is OK with passing the torch."

O'Brien paused for laughter, and added: "I allowed myself one, but it was a good one."

Longtime Leno detractor Jimmy Kimmel had kinder words for the departing host. Kimmel tweeted ahead of the show "Issues aside, 20 years at #1 is a remarkable achievement. Congratulations and best wishes to @jayleno on an incredible run."

Q&A: Jay Leno In-Depth: Post-'Tonight' Plans, Kimmel's Insults, Zucker, What He Taught Letterman

Meanwhile, Leno's longtime late night rival David Letterman held off on the jokes during The Late Show Thursday, instead simply congratulating Leno on his 22 years on the show.

"Congratulations on a wonderful run, and I'll tell you something -- If I was Jay Leno and I was retiring? You know what I would do? I'd go out and buy myself a car," Letterman said.

Leno successor Jimmy Fallon paid tribute to him.

VIDEO: Jay Leno's Best 'Tonight Show' Interviews

"To Jay, we say thank you very much. He's been a great guy. We're going to miss him," Fallon said during his Late Night monologue Thursday, before joking: "The ratings have been so good this last week because it's his last week that NBC is going to extend his week – so we're going to have another week of saying goodbye to Jay Leno."

Leno's final Tonight Show aired Thursday, with Billy Crystal, Garth Brooks and a slew of special guests toasting the king of late night. Read THR's full recap from backstage and the audience here.