Stephen Colbert said goodbye to "The Late Show" Thursday night in the franchise's finale following a 33-year run, saying he was "lucky enough to be here for the last 11 years," and couldn't take the experience for granted.

"There is so much history here in the Ed Sullivan Theater, and we've been honored to have been just a small part of it," Colbert said in his opening monologue. 

In the opening of the show, Colbert emphasized the "joy" the show brought him and cast members throughout the 11 years and over 1,800 episodes.

"We call it the joy machine, because to do this many shows, it has to be a machine. But the thing is, if you choose to do it with joy, it doesn't hurt as much when your fingers get caught in the gears," Colbert said. "And I cannot adequately explain to you what the people who work here have done for each other and how much we mean to each other."

The final show was packed with surprise cameos from celebrities such as comedian Tig Notaro, actors Ryan Reynolds, Paul Rudd, Bryan Cranston and Don Cheadle.

In the lead-up to the franchise finale, a stream of star guests had appeared on the show, such as actors Tom Hanks and Billy Crystal, director Steven Spielberg, David Letterman, the show's host when it debuted in 1993, Bruce Springsteen and Martha Stewart

Fellow late-night hosts Jimmy Kimmel, Jimmy Fallon, Seth Meyers and John Oliver also joined Colbert on an episode. In recognition of Colbert's final show, Kimmel and Fallon both aired reruns on Thursday.

CBS announced back in July that it would end "The Late Show with Stephen Colbert" and retire "The Late Show" franchise at the end of this season. The company said it was "purely a financial decision against a challenging backdrop in late night."

That explanation was met with skepticism from some viewers and media critics, who questioned whether political motives were involved, given Colbert's outspoken criticism of President Trump.

Colbert, 62, took over as host of "The Late Show" in September 2015 after Letterman retired from the role he'd held for 22 years.

The entire set of "The Late Show" is being donated to the Museum of Broadcast Communications in Chicago, a city where Colbert has deep roots. Colbert attended Northwestern University and performed in Chicago with the famous Second City improv troupe at the beginning of his comedy career. 

"The Late Show with Stephen Colbert" had been the No. 1 late-night program for nine consecutive seasons, CBS said last year. In September, it won the Emmy for outstanding talk series and received a standing ovation from the Emmys crowd.

CBS announced last month that Byron Allen's "Comics Unleashed" will replace Colbert's show in the 11:35 p.m. ET time slot.