The Big Bang Theory Shocker: Sheldon and Amy Have Sex!

Spoiler Alert!

After five years of non-physical dating, a break-up and a make-up, Sheldon (Jim Parsons) and Amy (Mayim Bialik) are going to get between the sheets for The Big Bang Theory‘s climatic winter finale!

“I was very surprised, but then I read it and it seemed absolutely the right time,” Parsons, who won three Emmys for his role as Sheldon Cooper, told Entertainment Tonight.

In the episode, which airs Dec. 17, the guys—Sheldon, Leonard (Johnny Galecki), Wolowitz (Simon Helberg) and Koothrappali (Kunal Nayyar)—are preparing for their big night—the opening of Star Wars: The Force Awakens—when Sheldon realizes it is the same night as Amy’s birthday.

At first he feels that she will understand if he skips her birthday, but then Penny (Kaley Cuoco) and Leonard convince him he has to put Amy first. After all, they just got back together. He can’t desert her on her birthday.

And when the late Professor Proton (guest star Bob Newhart) pops up in Sheldon’s dream dressed as Obi Wan Kenobi, he concurs with their advice.

Then Sheldon is left with the dilemma of what to give her for her birthday present and Amy’s friends agree that coitus is the best choice on Sheldon’s list.

Of course, no one on The Big Bang Theory can keep a secret, so Penny and Bernadette (Melissa Rauch) give Amy a head’s up. After all, a girl’s got to be prepared for such a big occasion.

“I was kind of nervous when I first saw where it was going—that it was going to feel voyeuristic or kind of icky, but it’s very tender. It’s very sweet,” Bialik told Entertainment Tonight.

So with Sheldon making the ultimate sacrifice, the guys have a big decision to make regarding who will get the fourth ticket to Star Wars. Who they pick is so obvious, you will be surprised it ends up happening by accident.

Can doing the deed compare to the premiere of Star Wars, which is also orgasmic for these nerds? You’ll have to tune in to find out.

The Big Bang Theory airs Thursdays at 8 p.m. ET/PT on CBS.