12/28/2011 11:24 am ET

'The Big Bang Theory' Celebrates 100th Episode: 'The Recombination Hypothesis' Will Explore Leonard And Penny's Future

The 100th episode of "The Big Bang Theory" (Thurs., 8 p.m. EST on CBS) might throw some fans for a loop, as the hit CBS sitcom dives into some most uncertain waters, as the show will test the hypothesis of Leonard (Johnny Galecki) and Penny’s (Kaley Cuoco) rocky relationship.

Although the two have recently split, leaving Leonard heartbroken, the unusual episode, titled "The Recombination Hypothesis," airing Jan. 19, will explore Leonard and Penny's past, present and future, as a scientific "what if" time-travelling situation.

“We went back and watched the pilot and we talked about that and we tried to do a 100th episode that connects emotionally to the pilot,” co-creator/EP Bill Prady told The Hollywood Reporter on the red carpet for "The Big Bang Theory's" milestone event. However, he called the episode "a little risky."

Series' star Cuoco echoed Prady's thoughts, calling the episode a creative departure from their normal format.

"This 100th episode is a real departure for us creatively," Cuoco told The Hollywood Reporter. "It’s definitely a different episode than we’ve done. It’s kind of a brain-teaser a bit; you don’t know what’s going on until then end. The end comes and then you realize it all makes sense."

Of course, this could all be heading into the direction of a cliche dream sequence, but Cuoco and the cast weren't going to give anything away.

"I think Leonard is especially hoping for reconciliation," Cuoco explained to The Hollywood Reporter. "The breakup between Leonard and Penny really put things in perspective for him; he’s heartbroken. As much as these two have had their friction, I don’t think they could survive without one another."

The 100th episode of "The Big Bang Theory" will air Thurs., Jan. 19 at 8 p.m. on CBS. Check out photos of the cast celebrating their 100th episode below.

WATCH: The cast reveals a few 100th episode secrets.