The truthiest late night talk show host signed off last night, with a heartfelt sing-a-long performed by actors, anchors, writers, inventors, musicians, diplomats, artists, a President and even a very large yellow bird and his cookie-obsessed friend. Stephen Colbert kicked off "We'll Meet Again" with Jon Stewart, as Randy Newman played the piano:

In his final The Colbert Report, he told his audience, "If all we achieved over the last nine years was to come into your home each night and help you make a difficult day a little better — man, what a waste... Nation I want you to know, if i had to do it all again, if I could do it with you, I would do it the same."

The Washington Post caught sight of these in the crowd singing, "We'll Meet Again," to Colbert:

Jeff Daniels, Sam Waterston, Keith Olbermann, Tom Brokaw, Katie Couric, Ken Burns, Howard Stern, Cory Booker, Bryan Cranston, Eleanor Holmes Norton, Charlie Rose, Tim Meadows, the Cookie Monster, James Franco, Toby Keith, Big Bird, Andy Cohen, Christiane Amanpour, David Gregory, Randy Newman, Willie Nelson, Doris Kearns Goodwin, Mandy Patinkin, Neil DeGrasse Tyson, Cyndi Lauper, Andrew Sullivan, Ric Ocasek, Michael Stipe, Kareem Abdul Jabar, Barry Manilow, Bill DeBlasio, Jeff Tweedy, Patrick Stewart, Stone Phillips, Arianna Huffington, Alan Alda, George Lucas, Alexai Lalas, Henry Kissinger, Elijah Wood, Mike Huckabee, Bob Costas, Nate Silver, Dan Savage, Thomas Friedman, Matt Taibbi, Mark Cuban and Paul Krugman.

Obviously others include Yo-Yo Ma, Dean Kamen, Samantha Power, Gloria Steinem, Vince Gilligan, Eliot Spitzer, President Bill Clinton (texting) and many more.

Alex Trebek and Santa also made cameos. Here's the whole show:

Colbert will be taking over The Late Show on CBS next September.