David Letterman is calling BS on CBS’ decision to cancel his successor Stephen Colbert’s “The Late Show.”

The veteran comedian, 78, shared a video montage of him roasting the TV network during his decades-long career of hosting “The Late Show” from 1993 to 2015.

“You can’t spell CBS without BS,” Letterman captioned the YouTube clip.

David Letterman has subtly weighed in on CBS’s decision to cancel his successor Stephen Colbert’s “The Late Show.” AP

The montage featured snippets from Letterman’s episodes in 1994, 2003, 2004, 2007, 2010, 2011, 2012 and 2013.

The timing of the video, which was shared Monday, has sent the rumor mill into overdrive, as it was shared just four days after CBS announced the cancellation of the series format after 10 years.

Colbert addressed the network’s decision during last Thursday’s taping at the Ed Sullivan Theater in NYC.

“Before we start the show, I want to let you know something that I found out just last night: Next year will be our last season,” he told the crowd. “The network will be ending ‘The Late Show’ in May.”

The news was met with loud boos from the audience.

“Yeah, I share your feelings,” he said. “It’s not just the end of our show, but it’s the end of ‘The Late Show’ on CBS. I’m not being replaced. This is all just going away.”

Colbert addressed the network’s decision during last Thursday’s taping at the Ed Sullivan Theater in NYC. CBS

Letterman shared a video montage of him roasting the TV network during his decades-long career of hosting “The Late Show” from 1993 to 2015. AP

“We get to do this show for each other, every day, all day, and I’ve had the pleasure and the responsibility of sharing what we do every day with you in front of this camera for the last 10 years,” he went on.

“And it’s a job that I’m looking forward to doing with this usual gang of idiots for another 10 months. It’s going to be fun.”

Since his announcement, a slew of comedy’s biggest stars — including Jimmy Fallon, Seth Meyers, John Oliver, Jon Stewart, Adam Sandler and more — have spoken out in support of Colbert.

The network has publicly cited financial reasons behind the decision to ax the show.

The network has cited financial reasons for axing the show. CBS

Notably, the announcement came just days after Colbert had ripped a $16 million settlement that Paramount, the parent company of CBS, had reached with the Trump administration.

Colbert, who is one of President Trump’s most persistent late-night critics, said the technical name in legal circles for the Paramount deal was “big fat bribe.”