Fans of the CBS show are trying to adjust to life without the show and never seeing new material from the cast again.
While the reception to the final episode was mixed, The Big Bang Theory fans are trying to relive every moment in order to cling onto the show.
In looking back through the 12 seasons of the show, one Reddit fan has noticed a fashion choice by Penny (played by Kaley Cuoco) is repeated when an important event is taking place.
Completing a huge full circle moment for Penny, Reddit user thegirlwholaughed revealed she wears a light blue t-shirt in the final episode that she is also seen wearing in the first ever episode.
The top has a purple flower design on one side and this is what made the fan realise it was the exact same one worn in season one.
It represents an important moment in Penny’s life as it is in the first ever episode that she meets future husband Leonard Hofstadter (Johnny Galecki) and his best friend Sheldon Cooper (Jim Parsons).
The trio’s meeting has shaped the success of the show and they have taken fans on their 12 seasons’ journey.
Then, in the final episode, she wears the t-shirt again and something else massive happens to her and will shape her future.
She announced her and Leonard were expecting their first child in emotional scenes that divided fans.
What’s more, another fan pointed out she has worn the outfit in other episodes where significant events have happened.
Reddit’s snazzy_E_4eva replied: “She also wore that shirt when Leonard asks penny out again after the breakup and after Priya. And they were unpacking Bernadette’s wedding gifts, just like penny was unpacking her move.”
Another fan pointed out that Sheldon was wearing a flash-themed t-shirt in both the first and final ever episodes, although it does not have the same significance as Penny’s.
Fans were confused why bosses decided to give Penny a baby over Amy Farrah Fowler (Mayim Bialik) given that Penny had said she did not want children many times.
However, producer Steve Holland told The Hollywood Reporter: “Leonard and Penny had been talking about having children – and the decision not to – this season.
“Their relationship was really the jumping off point of this whole show and it felt important to us to honour that relationship.
“I love them together and I wanted to know that they were ending in a happy place.”
Meanwhile, Kaley revealed on The Late Show with Stephen Colbert how hard it was for the cast to keep the ending a secret from fans.
Sheldon star Jim also added: “I was talking to one of the writers and he was like, ‘I’m nervous!’
“And I was like, ‘Well, you can’t get it wrong because it’s yours, you’ve been writing it all this time.’
“I said, ‘Look at it this way: You can’t get it right. It’s a series finale. Someone’s going to hate it.’”
The Big Bang Theory season 12 is available on CBS and All4.