Hey, remember when David Letterman starred in an '80s issue of the 'Avengers' comic book?

After more than three decades on late-night television, David Letterman will step down as host of the Late Show after tonight’s episode.

It’s no surprise that the cast of Marvel’s Avengers franchise — Robert Downey, Jr., Scarlett Johansson, Mark Ruffalo, Chris Hemsworth, Jeremy Renner, and Chris Evans — have all found the time to join Letterman for a chat. But Earth’s Mightiest Heroes and Indiana’s favorite son actually go back much further than that.

We promise we are not making this up: Letterman starred in issue #239 of the Avengers comic book in 1984 (as seen on Hero Complex and Comic Book Resources). And it was glorious.

Here’s the premise, as best we can understand it. Wonder Man, a munitions heir slash aspiring actor slash tragically forgettable superhero, gets booked on Late Night  (this was back before Dave decamped NBC for CBS) by his agent — on the condition that he bring the other, more interesting Avengers on the show with him. Fortunately, the Black Widow, Hawkeye, the Black Panther, and the Beast are all game.

But everything goes south when a baddie in the studio audience attacks the unsuspecting Avengers. It’s Dave himself who saves the day, smacking the villain over the head with a giant prop-comedy doorknob.

If the casting director for Captain America: Civil War is reading this, I can think of one showbiz vet who’s about to have a lot of free time on his hands.

Molly Fitzpatrick is senior editor of Fusion’s Pop & Culture section. Her interests include movies about movies, TV shows about TV shows, and movies about TV shows, but not so much TV shows about movies.