Big Bang Theory season 10 episode 11
Sheldon and Amy in The Big Bang Theory season 10 CBS

It is time for Sheldon Cooper and Amy Farrah Fowler's annual birthday coitus and the neuroscientist is going all out to seduce her boyfriend in the new episode of The Big Bang Theory season 10.

A promo released for episode 11 titled, The Birthday Synchronicity, shows Amy teasing Sheldon by putting on a Harry Potter robe. The video says, "Get ready for one magical night, in a Big Bang Special delivery" as Amy is seen in a wizard's robe and carrying a wand. "I thought I would let Harry Potter make things hotter," Amy tells Sheldon, who yells, "Wowzaa".

Then the scene changes to Howard checking Bernadette's contractions, as she has gone into labour. Following this, we see Sheldon and Amy kissing, which is interrupted by their neighbours. Penny knocks on the door and yells, "Bernadette's water broke," Leonard adds, "Come on everyone... to the hospital."

An irritated Amy yells out, "You have got to be kidding me!" In the fall finale episode of The Big Bang Theory season 9 (that aired on 15 December 2015), Sheldon and Amy finally get intimate and agree about making love at least once a year, on Amy's birthday.

Executive producer Steve Molaro then spoke to Variety about their annual event and revealed, "As far as this being some sort of sellout or giant shift in the character, I think it's lines like that that allow us to have such a momentous occasion, but it still can feel very much like Sheldon and Amy — Sheldon saying that we did this thing, but we're only going to do it once a year is an example of us holding the character intact, even when something this monumental happens."

The Big Bang Theory's fall finale episode will air on 15 December, at 8pm EST on CBS Network. The official synopsis reads as follows: