In the next episode of the "The Big Bang Theory" season 11, university researchers Howard Wolowitz (Simon Helberg) and Raj Koothrappali (Kunal Nayyar) go head-to-head with each other.

The trailer and synopsis for the upcoming installment titled "The Celebration Reverberation" were just released and they show Koothrappali confronting Wolowitz at the comic book store. "You're a grown man. Act like it," the engineer says to the astrophysicist, who is taken aback.

He immediately turns to him and replies, "Coming from a guy holding an 'Archie' comic." Wolowitz realizes that what he is holding does not actually make him look mature. Apparently, Koothrappali does not like it when his former friend makes fun of him. Wolowitz is known for making humorous remarks at the astrophysicist's expense and it looks like he may have gone too far.

Their mutual friend Leonard Hofstadter (Johnny Galecki) tries to make light of the situation and says to Koothrappali, "This fight either has to end or get way more entertaining." They are having lunch together with Sheldon Cooper (Jim Parsons) but Wolowitz is not with them.

Moments later, the engineer walks over to their table and gives Koothrappali a mocking grin. In another scene, the two find themselves in a children's bouncy house and push each other. However, both of them bounce back and appear to be having fun but don't show it on their faces.

In the last episode, Koothrappali decided to stay away from his longtime friend Wolowitz because he thought that the engineer made him less confident about himself. It seemed like his decision may have worked because he was able to land a job at the planetarium. His confidence grew considerably since then without Wolowitz.

"The Big Bang Theory" season 11 episode 11 will hit the airwaves on Thursday, Dec. 14 at 8 p.m. EST on CBS.