It is time for the much awaited intimate scene between Sheldon (Jim Parsons) and Amy (Mayim Bialik) in the upcoming fall finale of the hit CBS series "The Big Bang Theory."

In "The Opening Night Excitation," the promo shows the pair sitting side-by-side in bed wearing their chaste nightdress. They are greeting each other awkwardly, as the situation is not something they have encountered before in their five years of being together. Prior to the destined night, Penny (Kaley Cuoco) and Bernadette (Melissa Rauch) are happily telling a shocked Amy that Sheldon is finally ready to get "physical." Amy tells them to shut up and then sits down, as if trying to absorb what she just heard. She tells them she does not know what to say or do. After a while, she jumps up and announces that she needs to get waxed and rushes off somewhere.

The clip also shows Arthur Jeffries aka Dr. Proton (Bob Newhart) appearing to Sheldon as a sort of mirage. The phantasm is wearing some Star Wars-inspired wardrobe and appears to be as confused as Sheldon, who has just been roused from his sleep. Speculations claim that the professor is there to advice the genius physicist on what to give his girlfriend for her birthday. This is where Sheldon will reportedly have an epiphany that he does not need to buy her anything. His body will be enough.

During their interview with ET Online, Parson playfully said that his character's coupling with Amy was like "putting the 'bang' into the theory." He also revealed that he did not have a hard time acting the part in the intimate scene. Meanwhile, Bialik admitted to being nervous about it, thinking the scene would feel "voyeuristic." She said, however, that it was not what she expected, as it turned out to be "very tender" and "sweet."

"The Big Bang Theory" season 9 fall finale will air on Thursdays, Dec. 17, at 8 p.m. EST on CBS.