Before The Walking Dead sold 45 million copies, author Robert Kirkman was told "zombie books don't sell"

Robert Kirkman will likely be dining out on this anecdote until the end of his career – and we're not talking about munching on brains here.

According to former Image Comics publisher Jim Valentino on Robservations with Rob Liefeld (H/T Popverse), Kirkman was once told "zombie books don't sell."

"Walking Dead from the time it was published had a positive sales slope," Valentino recalled. “And [Robert Kirkman] loves to tell this story, because I told him zombie books don’t sell."

In Valentino's defense, he added, "I wouldn’t consider Walking Dead a zombie book. It’s a survival book."

In a slightly more mortifying recollection for Kirkman, Valentino went through some of the legendary comic creator's initial title pitches for The Walking Dead.

“[Kirkman] hit me with the first thing which was, ‘I want to call it The Dawn of the Dead.’ No Robert, you can’t do that. It’s already a movie. ‘What do you think of Planet of the Zombies?’ Kirkman [then] says, ‘How about The Walking Dead?’ Boom. That's it. Call it The Walking Dead."

As of the last official count by Image Comics, The Walking Dead is up to over 45 million copies sold, as well as spawning a hugely successful TV show (which ran for 11 seasons on AMC), multiple spin-offs, novels, and video games, including the acclaimed Telltale series. Not bad going for a zombie book.

Next up for Kirkman is his job overseeing Invincible season 4, which includes an original storyline that never made its way into the comics on Prime Video. The episode features Steven Yeun's Mark Grayson coming into contact with a few hellish figures, including Damien Darkblood (Clancy Brown) and Satan (Bruce Campbell) himself.

For more, check out our guide on how to watch The Walking Dead in order and our picks for the best Prime Video shows.