'Big Bang Theory' star Johnny Galecki admits he was the only one to have sex in his dressing room

Now that “The Big Bang Theory” has finally come to an end, the cast is getting brutally honest about their time on the set.

Johnny Galecki, who played Leonard Hofstadter on all 12 seasons of the hit CBS sitcom revealed that he was the only one to have sex in his dressing room. He was joined by the rest of the cast for a retrospective on “The Late Show with Stephen Colbert” after the highly anticipated finale aired. The host asked the cast questions that they anonymously submitted to one another when Galecki dropped the bombshell.

Simon Helberg, better known as Howard Wolowitz, noted that he believed Galecki had done the deed in his backstage room. The 44-year-old former “Roseanne” star sheepishly raised his hand confirming that he was the only one that had.

“That did not include me,” his co-star and ex-girlfriend Kaley Cuoco, 33, quickly clarified.

“We all use Johnny’s dressing room,” Helberg joked.

The long-running series on CBS concluded with two back-to-back episodes, "The Change Constant" and "The Stockholm Syndrome," in an hourlong finale Thursday evening. The series exited the airwaves with the most episodes for a multicamera series ever with 279 episodes. It edged past NBC's "Cheers," which aired for 12 seasons and 275 episodes.

Helberg jokingly took shots at “Cheers” throughout the interview noting that he was pleased to beat the classic sitcom’s run.

Colbert also asked Galecki about being a self-described “theater rat” and wondered what animal he’d describe Cuoco as.

“Be careful,” she warned.

“I’m sitting too close. I’m going to get punched,” Galecki responded before deciding that she’d be “an Arabian pretty horse.”

The answer was a clear nod to the actress’ equestrian hobby.