The cast of the sitcom - Kaley Cuoco, Jim Parsons, Mayim Bialik, Melissa Rauch, Simon Helberg, and Kunal Nayyar - sat down for a group interview on "The Late Show with Stephen Colbert" on Thursday night, May 16 to discuss the last-ever episode of the show, which had aired shortly before.
During a lightning round of questions, the actors submitted anonymous queries and Stephen Colbert asked, "Did anyone ever have sex in their dressing room? Show of hands".
None of the actors were quick to make a confession, but Kaley turned to her onscreen love interest Johnny and said, "You must have" and Kunal joined in, before Johnny eventually put his hand up.
Kaley also acknowledged the fact that she had dated him for two years until 2009 when she stated, "And that did not include me, just FYI (for your information)".
Johnny, who is expecting his first child with girlfriend Alaina Meyer, laughed and added, "I have to be honest".
Elsewhere in the interview, the cast praised the writers for how they concluded their characters' storylines, with Kaley saying, "It was not an easy feat... We had a lot of anxieties about how this was going to go, us as actors, the writers, there's a lot of pressure on how to end this and fans wanted to know what was going to happen so it was tough and I think that they did it brilliantly".
Johnny added that "the writers did an incredible job" while Jim said some series finales in history have been divisive among viewers but he can't imagine many fans of the show disliking its conclusion.
The cast also revealed that the last day on set, after 12 seasons and 279 episodes, felt like the last day of school because the crew had made yearbooks containing school-style portraits of everybody across all 12 years.