Definitely you don’t want to miss tonight episode of “The Big Bang Theory” because it’s gonna be a big, really big, night for Sheldon and Amy.

Warning! spoiler ahead

According to USA Today, Sheldon Cooper (Jim Parsons) will make an unprecedented choice in tonight’s episode, titled “”The Opening Night Excitation.”

The super-nerd professor will choose sex with girlfriend Amy (Mayim Bialik) instead of going to the premiere of his favorite movie of all time “Star Wars”.

Sheldon will pick sex and will celebrate Amy’s birthday by sleeping together for the first time. But he doesn’t completely shut out “Star Wars: The Force Awakens” and will consult one of his science heroes, the late Arthur Jeffries, who is transformed into Obi-Wan Kenobi in Sheldon’s subconscious.

The synopsis of tonight’s episode reads:”After more than five years of dating, Sheldon and Amy spend their first night together. Also, Leonard, Wolowitz, and Koothrappali must decide who will take their extra Star Wars movie ticket.”

Watch episode 11 sneak peak here

Sheldon and Amy recently got back together after they broke up because of Cooper’s strange way of showing his affection to Amy.  The couple have been dating for five seasons after meeting through an online dating site. quoted Bialik saying: “Amy’s been eager all along for a different kind of connection, but it’s actually initiated by Sheldon.”

Parson, on the other hand, said: “Sheldon’s eager for her to know she’s special to him, and this is one of the items on the list that he feels could show that.”

When asked if having their “coitus” would mean the two character will be together forever, co-creator Chuck Lorre said: “That’s a terrific question. Lots can happen in this world. A few years ago, if you had asked me if we would be discussing this story, I would have said, ‘Not a chance.’ So, I’m going to shut up now and not presume to know what’s coming.”

“The Big Bang Theory” airs tonight (Dec 17) at 8 p.m. EDT on CBS.