He filled in at the last minute after Sen. John McCain canceled, and still MSNBC's Keith Olbermann was nearly upstaged by the Republican nominee for president Wednesday night on the Late Show.

Several times during the two-segment interview with Olbermann, David Letterman showed McCain during various stages of his interview with Katie Couric, including McCain getting some make-up applied. The Couric interview was being taped at the same time at CBS News headquarters a few blocks from the Ed Sullivan Theatre, home of the the Late Show. Letterman was not pleased that McCain canceled on his show, only to turn up on the set of the CBS Evening News.

Between McCain questions, Letterman did ask Olbermann about his and Chris Matthews' removal as MSNBC's political anchors:

Olbermann: "We're not the anchors anymore. We're just going to be commentators."
Letterman: "Are you all right with that?
Olbermann: Yeah, because I'm actually going to be on more than I was previously and I can say what I think, rather than sitting there saying, 'now here's more from such and sum over there.' Basically I can sit there and between appearances eat ice cream."
Letterman: "So things are better this way, you're saying?"
Olbermann: "Yeah, they actually are. They're certainly easier and I can enjoy election night."

Letterman thanked Olbermann, calling him "a true gentleman."

And later, not giving up on the McCain cancellation rant, Letterman joked, "We're told now that the senator has concluded his interview with Katie Couric, he's now on Rachel Ray's show making veal piccata."