As you know, "TBBT's" series finale airs, Thursday, May 16. It's been a long and dreadful realization for the "Big Bang Theory" cast. Each member has said his and her goodbyes in a multitude of ways. There have been many tears shed between cast members, as well as fans. However, in a recent interview with Hollywood Reporter, Jim Parsons shared a particularly interesting bit of information about the show's cancellation.

Basically, this final "theory" was his call.

'Big Bang's series finale depended on 'Sheldon'

What's TBBT without "Sheldon Cooper"? After 12 seasons, there's seriously no replacement for his character, or any other "Big Bang" cast member. It's a family you've all grown to love and cherish as a unit. The entire thing falls apart without either of its components. Well, according to the interview with Hollywood Reporter, that's seemingly what happened regarding "Big Bang Theory," effectively bringing about the series finale.

Jim Parsons, a.k.a "Sheldon Cooper," is walking away from the show. He says it's not anything anyone has done, nor is it any type of irritation with the series.

Instead, Parsons just feels like it's time to "move on." According to Jim, when the realization hit, that he possibly didn't want to re-up his contract for another term, he said it was also his answer concerning whether or not to walk away from "Big Bang Theory."

"There was no factor; there was no situation that I was like, 'Well, I've had enough of that.' No," TBBT's Jim Parsons mentions during the interview. "There was nothing like that. It was just…when you know, you know." According to the "Sheldon Cooper" actor, when you get to a certain age, you tend to think differently about your life. The Big Bang Theory would not be the same with a "Sheldon" replacement. Who else could ever whip up theory like Jim Parsons' character?

So, with that in mind, the cast agreed to bring the show to an end.

Accordingly, the show's co-creator, Chuck Lorre, says he just couldn't fathom going on without the entire cast. He notes that this particular cast is a big reason why "Big Bang" succeeded. Lorre says he's seen other shows attempt moving on without one of the main characters, and they've usually failed. Specifically, as success stories go, he mentioned "Frasier" as possibly being the only one he could recall.

'Sheldon' now vs 'Sheldon' 12 years ago

According to Jim, there's a big difference in his character than when the show first began. Just as people change, this "Big Bang" cast member's role also changed.

Jim Parsons says to Hollywood Reporter that sometimes he even has trouble with Sheldon's lines now, and he doesn't know why.

And possibly, the character has become more difficult for him to execute. "And I don't know what that means but it's like you just change," Parsons states to the source. So, while he's ahead, Jim has decided to call it quits.