The story was sort of a dark showbiz satire centered on a TV talk show. As best I can recall at this distance of time, the host, played by Dick Shawn, was lunatic and ultimately had to be replaced. And there was an intense "behind-the-scenes" competition between two guys over who would replace him. And the big twist is that at the very end, neither of them get the job, but it goes to a stand-up comic who had appeared on the talk show and done well, standing up to the host. The choice was a surprise because the actor playing the comic was only 10th-billed on screen and (in real life) not very well known. His name was -- David Letterman.
I swear this is true. You can check out the full credits here on iMDB, but here's site's billing --
Just to put this in proper perspective, this was a year before he got his own short-lived morning show on NBC, and three years before his Late Night program began on the network.
By the way, just to tie this into an earlier post, one of the TV movie's stars, Edie Adams, was the wife of Ernie Kovacs.
I tried to track down a video clip of Dave's appearance in the film, but not only couldn't find one, I couldn't find anything from the movie. But I'm sure a national TV show could have had the resources to track something down. I realize that this qualifies as a Little Known Fact -- and even far lesser known to have actually seen it. But anyone putting together a feature on Letterman should have been able to come across it pretty easily: you look up his credits on iMBD (something pretty basic to do), and look through them. There aren't many acting jobs to go through, and when one of them popped up as being about a talk show, that should have set off alarms.
Ah, well. Maybe someday footage will show up. Until then, the mere whimsy of it is almost enough, just to know. And I couldn't let the day pass without mentioning it.