Sir Paul McCartney to be Stephen Colbert's Final Late Show Guest

Sir Paul McCartney will be the final guest on The Late Show with Stephen Colbert, with the legendary musician sitting down with the host for a chat about the Beatles, his latest album and his frustration with iPhone updates.

Amid speculation as to who would grace the couch at the Ed Sullivan Theater for the final time — and an extended riff on whether Colbert would land Pope Leo XIV, often mentioned as his ideal interviewee — Sir Paul strode onto the stage to applause from the audience, in the theatre where the Beatles made their first US TV appearance in 1964.

The reveal came after Colbert first addressed the audience in a more intimate style than his typical monologue, leaning on his desk as he spoke about the joy hosting The Late Show has brought to him and his staff over the past 11 years.

"This show, I want you to know, has been a joy for us to do for you," he said.

He also referenced his previous comedy persona — the fictional conservative cable host of the same name, from his days on Comedy Central — and spoke about how his time helming CBS's flagship late-night franchise had been different.

"On night one of The Colbert Report back in the day, I said anyone can read the news to you. I promised to feel the news at you," he said.

"And I realised pretty soon in this job, that our job over here was different.

The Late Show's cancellation was officially announced last July, setting off a storm of controversy as it came while CBS's parent company, Paramount, was seeking FCC approval for a merger with Skydance, creating one of America's largest entertainment companies.

Colbert, one of US President Donald Trump's most vocal critics, had just days earlier castigated CBS for settling a lawsuit filed by the president against 60 Minutes for $US16 million ($22 million), despite many legal experts believing the case had little chance of success (Colbert called the settlement a "big fat bribe").

Colbert has mercilessly joked about the network's decision in the months following the announcement, including by inviting former Late Show host David Letterman onto the roof of the Ed Sullivan Theater to engage in "wanton destruction of CBS property".