Remember Big Bang Theory's epic 100th episode? How can you not? Last year, Kaley Cuoco told us about the episode: "It's like one we've never done before. It's kind of a mind game. You won't figure it out until the end."
And now, in this exclusive clip from The Big Bang Theory: The Complete Fifth Season (out tomorrow), you'll hear from stars Johnny Galecki, Cuoco and more about how they felt about the 100th episode, and why it was huge for Leonard and Penny.
"The stuff with Leonard and Penny is always tough to predict because there are two very passionate camps about whether or not they should be together," Galecki says in the featurette. To get the behind-the-scenes scoop from BBT's big 100th episode, check out the clip below!