AMC's The Walking Dead seems like the kind of show that the characters on CBS' The Big Bang Theory would discuss and pick apart for its use of zombie tropes. However, the two shows have another, surprisingly direct connection in the form of one particular actor who appears on both.

The actor in question is Steven Yeun, who plays the wealthy but ultimately hapless Glenn Rhee on The Walking Dead. Jeffrey Dean Morgan's villain became the protagonist Negan famously kills Glenn and Abraham Ford (Michael Cudlitz) in the show's seventh season premiere, "The Day You'll Be Gone." As it happens, a similarly sudden (though far less baseball bat-happy) exit happens to Yeon's "The Big Bang Theory" character Sebastian, who appears briefly in Season 3, Episode 22, "Staircase Implementation."

Appearing exclusively in a flashback showing Leonard Hofstadter's (Johnny Galecki) first impressions of his future roommate Sheldon Cooper (Jim Parsons), Yeun's Sebastian appears as a former resident who exits the building with some speed after enduring Sheldon's antics in earnest recommends that too. Bega and Leonard. This is all we ever learn about poor Sebastian, and all of Sheldon's weird and horrible things that he heavily implied he faced are left forever unresolved. Based on the trials of the roommates that Leonard must go through as the flashback continues, however, it can't be very easy.

From Star Trek actors enter. of Sean Astin (whose own the look left Mayim Bialik star-struck), The Big Bang Theory has no shortage of legendary cameos and full-on guest stars. In retrospect, Steven Yeun's appearance as Sebastian is especially significant because it happened in 2010, right before he broke as Glenn. Yeun has since gone on to a stellar career in films such as Lee Isaac Chung's Minari (for which he was nominated for an Academy Award for Best Actor) and Jordan Peele's None, as well as series such as Beef and the animated superhero saga Invincible. .

Talking to Interview magazine back in 2011, Yeun addressed his work on The Big Bang Theory and its significance to his career, revealing that it was one of the first things he did outside of theater after moving to Los Angeles. He also opened up about how he landed the role, explaining:

“The first thing I put down was three ads in one sitting. It was great. They kept me alive for a while. Then I tested for an ABC pilot that I didn't get, but the casting director threw me a small part on 'The Big Bang Theory.' After that was The Walking Dead. It was a very happy six months."

The Big Bang Theory is currently streaming in its entirety on Max.