VIDEO: The Colbert Report Says Goodbye with Massive Celebrity Sing-Along

Stephen Colbert said goodbye Thursday night to The Colbert Report and the character he's played for the past nine years.

"Folks, if this is your first time turning in to The Colbert Report, I have some terrible news. This in fact is your last time tuning in to The Colbert Report," the host said. "Until 10 years from now when they reboot it directed by J.J. Abrams."

Colbert, who will take over Late Show next summer, then launched into his final Word, "Same to You, Pal," which gave him an excuse to reflect on how little has changed since the Report debuted in 2005 (a Bush governor running for president, troops going to Iraq, etc).

"The truthiness is all those incredible things people say I did — running for president, saving the Olympics, Colbert Super PAC, treadmill in space, the Rally to Restore Sanity and/or Rear and/or Cat Stevens' career — none of that was really me. You, the Nation, did all of that. I just got paid for it," Colbert said.

Colbert then welcomed Grimmy (aka the Grim Reaper) onto the show for the recurring segment "Cheating Death with Stephen T. Colbert, D.F.A." Only their intro took a dramatic turn when Colbert accidentally killed Grimmy, thus defeating Death and becoming immortal.

"Now that I can't die, I guess I won't need my bucket list anymore," Colbert mused. "There's a lot of good stuff on here. Visit every continent. Go bungee-jumping. Chicken wings. Popcorn shrimp. Nachos. It kind of turned into a list of things I wanted to eat out of a bucket. The point is, I'm ending the Report and I was going to say goodbye, but now that I'll live forever, who knows?" Colbert said, launching into "We'll Meet Again."

Randy Newman accompanied Colbert on piano, while the host was joined by Jon Stewart, Bryan Cranston, Willie Nelson, Mandy Patinkin, Neil deGrasse Tyson, Big Bird, Patrick Stewart, Cyndi Lauper, Sam Waterston, Barry Manilow, Katie Couric, Gloria Steinem, Cookie Monster, George Lucas, Alan Alda, James Franco, Jeff Daniels, Kareem Abdul-Jabbar, Andy Cohen, Colin Meloy of the Decemberists, Tom Brokaw, Ariana Huffington, New Jersey Sen. Cory Booker, Elijah Wood, former New York Gov. Eliot Spitzer, Grover Norquist, Michael Stipe, Tim Meadows, Keith Olbermann, Shane Smith, Ken Burns, Mark Cuban, Paul Krugman, Mike Huckabee, and Henry Kissinger.

Vince Gillian, who is still being held captive in Colbert's basement, joined in via video, as did the host's Latino alter ego Esteban Colberto, Bill Clinton, an astronaut running on the C.O.L.B.E.R.T. treadmill in space and Smaug the dragon.

Colbert then journeyed to the roof of the building, where, dressed like Captain America, he met up with fellow immortals Santa, Abraham Lincoln (who, it turns out, is a unicorn) and "the one with all the answers," Alex Trebek, so they could fly off together in the reindeer-lead sleigh.

I changed the world!

— Stephen Colbert (@StephenAtHome) December 19, 2014