The first half of Season 9 of "The Big Bang Theory" will end with a bang on Thursday as Sheldon and Amy will finally consummate their relationship and Bob Newhart will reprise his role as Sheldon's Obi-Wan Kenobi.

Last week the lyrics of a Beach Boys song helped Sheldon (Jim Parsons) realized how much Amy (Mayim Bialik) has done for him and how much she really means to him. After coming to this realization, he confessed to Amy that he loved her and the two shared a passionate kiss. They also agreed to get back together.

In the upcoming episode, which is titled "The Opening Night Excitation," the two lovebirds will take their awkward romance to the next level after Sheldon decides to give Amy the gift of intimacy for her birthday.

A promo shows that Amy will be overjoyed when she learns that Sheldon plans to get physical with her.

"After over five years of dating, we felt the time was right for Sheldon and Amy to finally consummate their relationship, and we're so excited for the audience to see the journey over the next several episodes," said executive producer Steve Molaro to Variety.

To add to the magnitude of this monumental moment in the series, Newhart will return as the dearly departed Professor Proton. According to ETonline, the legendary actor will sport his Obi-Wan Kenobi costume and appear to Sheldon in several dreams to give him guidance about a very important decision.

The synopsis for next week's episode, "The Opening Night Excitation" reads as follows:

"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, on THE BIG BANG THEORY, Thursday, Dec.17 (8:00-8:31 PM, ET/PT), on the CBS Television Network. Emmy Award winner Bob Newhart returns as Sheldon's Obi-Wan Kenobi."

Season 9, Episode 11, " The Opening Night Excitation," will premiere on Thursday, Dec. 17 at 8 p.m. ET on CBS.

Watch a preview below.