The big bang theory season 8
Sheldon with an engagement ring in The Big Bang theory season 8 finale CBS

The Big Bang Theory season 8 concluded on a sad note for Sheldon and Amy, where the neurobiologist breaks up with Dr Cooper, but it turned out that he was planning to propose to her.

Several fan theories suggesting that the couple will reunite in season 9 have surfaced.

A Reddit user predicts that Amy and Sheldon will get together in the first few episodes, but Mary Cooper might not approve of their relationship.

He wrote, "I have a prediction that Amy and Sheldon get together in the first few episodes and engaged as well. But last episode they plan a wedding date and Sheldon informs his mother, when Mrs. Cooper meets Amy she instantly hates her because Amy does not believe in god hence causing a stir between Sheldon and his mother."

Another user suggested that, "Amy wants to be with Sheldon, and she knows that Sheldon also wants to be with her, but she also knows she needs to make him fight for her. The process of fighting for her will, of course, involve some major self-discovery."

Yet another Reddit user predicts that the lead couple will break up, only to reunite by the end of season 9.

"I think Amy is going to leave Sheldon. This will lead to a season of random dates. Maybe a new group member, Sheldon will be an asshole to him. Finally, after a season of Sheldon pining away and Amy trying to move on, 1 of 2 things. 1. They get into a fight and have a passionate kiss. 2. They get into a fight and end up in bed, which will probably be the cliff hanger scene for the season."

Showrunner Steve Molaro dished on Sheldon-Amy's sad ending and teases the real reason behind their break-up.

Molaro told The Hollywood Reporter, "We don't know exactly where they are but after five years, I think the answer is in the question. They have been dating, this is the fifth anniversary of their first date, and she can't even get through a make-out session without him thinking about television, so I understand her frustration.

"At the same time, I understand his side, which is: How much faster do you think I can go with this? It's an interesting place for them to be; it seems very real and I think it's exciting that we're shaking things up," he added.

How long will the break-up last?

"I don't know if the length of time matters so much as the situation where Amy has taken a legitimate step back that he was not expecting. That's really the headline here that we'll be digging into," Molaro teased.