Paul McCartney performed "Hello, Goodbye" with Stephen Colbert on the final "The Late Show" episode. Watch the performance.

Paul McCartney was Stephen Colbert's final guest on 'The Late Show' Thursday night before things took a surreal turn.

He served as Colbert's final guest, playing on the same stage where the Beatles famously performed on 'The Ed Sullivan Show.'

CBS aired its final installment of The Late Show tonight, with Stephen Colbert—class act that he is—starting things off with a reminder that he has always referred to the series as “the joy machine,” before gently letting a wide swathe of cameoing celebrities down in their dreams of being his “last guest.

It was a starry night for Stephen Colbert's "Late Show" finale. Here's who showed up to the last episode along with Ryan Reynolds, Paul Rudd and more.

A bittersweet but fitting farewell for The Late Show with Stephen Colbert, as the celebrated talk show host signed off the final episode with special guests, including Sir Paul McCartney. The