Jim Parsons explains why he walked away from The Big Bang Theory. A month before the CBS sitcom premiered season 12, it was announced that it was ending, with its upcoming outing set to be its last. This came as a shock to many, since the network had hinted at a season 13 not long before, and the show continued to perform well in terms of ratings. But as it turns out, the reason boiled down to one of the show's main leads no longer wanting to return past its 12th year.

Debuting in 2007, Parson's Sheldon Cooper was among the first characters cast for The Big Bang Theory, alongside Johnny Galecki's Leonard. The sitcom's unaired pilot with a different female lead received primarily negative reviews, leading it to be reshot with Kaley Cuoco's Penny, Simon Helberg' Howard and Kunal Nayyar's Raj. By season 4, recurring guest stars Melissa Rauch (Bernadette) and Mayim Bialik (Amy) were promoted to series regulars, fully filling out the cast. The Pasadena-based gang of seven remained tight until the very final episode of the show, which was arguably one of the most touching sitcom finales in recent memory. But the series could have continued had it not been for Parsons decision to leave, a choice he said just all of a sudden came to him.

Related: Everything We Know About The Big Bang Theory's Future

Speaking with THR in light of The Big Bang Theory's sendoff, Parsons details how he came to the realization that it was time to move on from the show, despite the hefty paychecks he and his co-stars enjoy per episode (reportedly $1 million). As it turns out, it wasn't planned - one day, he simply realized that he no longer wanted to return after season 12. There were no negative external factors that drove his decision, he just genuinely thought it was time to move forward with his career.

"It was the first time in my life of doing this show that it occurred to me that I might want to not do another contract after [season] 12 was up. I don't know if it's because I'm an Aries or just because maybe I'm in touch with myself. Whatever it is, once I had that thought, I was like, 'Well, that's your answer.'"

"There was no factor; there was no situation that I was like, 'Well, I've had enough of that.' No. There was nothing like that. It was just…when you know, you know. And you're susceptible and thrown around by the whims of your own existence and getting to a certain age and your life changes and suddenly you just think different. It has been fascinating to think about who I was 12 years ago. And sometimes when I have trouble learning a line or saying a line of Sheldon's right now, it's hard to know why specifically. But it's like, you're not the same person you were. There is a possibility that this actually became more difficult for you in a way. And I don't know what that means but it's like you just change."

The Big Bang Theory cast eating together

In a previous interview, Parsons defended his decision, saying that while there was really no reason to stop doing The Big Bang Theory, it felt like they had done everything they could with the show. Since Sheldon is such a significant part on why The Big Bang Theory works, creator Chuck Lorre and CBS decided it was best to end the series rather than continue without him. Considering the tremendous character arc Sheldon had had in the course of 12 years, that's true. However, since most of the show's narrative, particularly the last couple of seasons, were focused on him and his life, some of the other characters were sidelined. The  series finale may have rectified some of that with teases of a new beginning for Penny and Leonard, but there are a couple of ways that the show could've continued without being boring.

With The Big Bang Theory now officially over, one wonders how CBS plans to make up for the massive void it leaves in their programming line-up. Its spinoff, Young Sheldon, has already been renewed for two more seasons and is being positioned to take its place, but the network could surely milk the long-running sitcom's popularity by launching another offshoot if it wanted to. There's no word regarding that as of now, with Lorre maintaining that the only time he'll push for one is if they have the right story. But having another spinoff is not really outside the realm of possibility, and fans would likely give it a shot.

More: The Big Bang Theory Ending: Everything That Happened In The Series Finale

Source: THR