Well, Metro faithful, tonight’s the night we say goodbye to an American -- and broadcast -- original. David Letterman.

And on such occasions, there must be cake.

If you caught Tuesday night’s second to last show, you’ll know there was a giant cake on the stage of the Ed Sullivan Theater, with the words “Goodbye Dave” piped onto it.

And out of it popped another original, funnyman Bill Murray, in fog glasses and coveralls, who hugged the 68-year-old talk show great and smeared cake on his hair.

He fist-bumped music man Paul Shaffer and smeared  cake on members of the audience -- including a woman he kissed.

Then, he and Letterman did what they did when Murray, 64, was his very first guest in 1982 on NBC. They bantered and chewed the fat.

Murray was also Letterman’s first guest when he moved to CBS in 1993 and was likely the last sit-down guest, too. There are no interview guests set for Wednesday night’s final show.

The New York Times’ John Koblin has perhaps best summed up the significance of Letterman’s final show.

“On Wednesday night on CBS, after 33 years as a host, the longest late-night tenure ever, Mr. Letterman will close out his career with his 6,028th episode. His influence has been substantial: He breathed new life into the talk show, taking it beyond the traditional desk-and-sofa interview sessions with an array of innovative, often outlandish antics; he gave birth to many careers; he became a role model for a generation of comedians, including most of the current late-night roster; and he turned signature segments like Stupid Pet Tricks and his Top 10 list into American cultural institutions,” Koblin wrote Tuesday.

“He was more inventive and more creative with this form than anyone before or since,” Jerry Seinfeld told The Times.