The Big Bang Theory's Kunal Nayyar reveals some behind-the-scenes factoids about the famous apartment set and a disgusting habit Johnny Galecki had.

The Big Bang Theory's Kunal Nayyar recently discussed some behind-the-scenes secrets, including a strange habit of co-star Johnny Galecki's. The popular sitcom ran on CBS for 12 seasons, ending in 2019. It followed a group of scientists and those surrounding them as they progressed through their daily lives. CBS announced a prequel series in 2016, and Young Sheldon aired in September 2017.

The show's standout character is arguably Sheldon Cooper, the prequel series' namesake, a theoretical physicist portrayed by Jim Parsons in The Big Bang Theory. His friends include Nayyar's character, Raj Koothrappali, Galecki's Leonard Hofstadter, Simon Helberg's Howard Wolowitz, and Kaley Cuoco's Penny. Like some other sitcoms - even in the present day - The Big Bang Theory is filmed in front of a live studio audience, produced by Warner Bros. Television and Chuck Lorre Productions.

Reported by the Daily Express, Nayyar appeared on the British television program, Sunday Brunch, and unveiled some trivia about the filming process in Sheldon, Leonard, and Penny's apartment complex. He says that any shots involving characters walking up and down the apartment stairs took place on prop stairs that "go nowhere" and that the actors would have to hold at the ends of the stairs while the set changed to resemble a different floor. When going downstairs, there was nothing but a wall "where Johnny Galecki, for 12 years, would stick his chewing gum on." Read Nayyar's full quote below:

"You run back up the stairs, that go nowhere, and then you walk back down as if it's a new floor. Down there is nothing. There's a wall there where Johnny Galecki, for 12 years, would stick his chewing gum on. I'm not joking. So, if any of you are Johnny Galecki fans and you want his dried chewing gum, I am sure it's for sale somewhere on the internet. Welcome to Hollywood."

Behind-the-scenes trivia is often interesting for film and TV fans, even if it can reveal some "movie magic" that filmmakers or stars would prefer to keep secret to maintain that all-important suspension of disbelief. The staircase shooting technique is one of those moments that feel seamless when watching The Big Bang Theory, but the fact that there's a wall covered in an actor's gum at the very bottom is far from anything that fans of the show would probably imagine. Galecki's behavior is also far from the grossest thing an actor has done on set if some of the things done while filming 90 Day Fiancé are any indication.

Galecki hasn't had a chance to respond about this rather disgusting revelation, but his commitment to the act is commendable if nothing else. It also lends to some intriguing talk-show trivia and the prospect that the star's dried chewing gum is "for sale somewhere on the internet," as Nayyar says. That realization is also gross in and of itself, but hardcore Galecki fans might disagree. It wouldn't be the first time that somebody has sought out unconventional props or other such things that an actor has interacted with to add to their collection. That is, of course, if anything even remains of The Big Bang Theory's set, which got torn down at the end of the show's run. Since the finale, which almost went for two more seasons at CBS, Galecki's wall of gum could merely be a part of TV history.