'Big Bang Theory' reportedly ending because Jim Parsons didn't want to keep going

"The Relationship Diremption" -- Sheldon (Jim Parsons) faces a personal crisis after deciding he’s wasting his time with string theory, on THE BIG BANG THEORY, Thursday, April 10 (8:00-8:31 PM, ET/PT) on the CBS Television Network. Photo: Sonja Flemming/CBS ©2014 CBS Broadcasting, Inc. All Rights Reserved (©2014 CBS Broadcasting, Inc. All Rights Reserved)

Following the news that CBS’ hit sitcom “The Big Bang Theory” will end in 2019, fans may now have more of an idea about why the decision was made. It seems that one of the show’s key stars Jim Parsons was ready to step away from his role.

According to Entertainment Weekly, Parsons went into negotiations for another two seasons already in the mindset of leaving the role of Sheldon Cooper behind.

According to Entertainment Weekly, the 45-year-old star opted to move on. While the show is an ensemble, Parsons’ character is perhaps the most well-known and beloved of all the characters, with many storylines revolving around his high-maintenance attitude. Multiple outlets speculate that the decision was made to end the show with the full cast rather than try and mush on without the gang’s core character.

The show also stars Kaley Cuoco, Johnny Galecki, Kunal Nayyar, Mayim Bialik, Melissa Rauch and Simon Helberg.

Reps for Parsons did not immediately respond to Fox News’ request for comment.

However, the star did post a lengthy statement on Instagram expressing his gratitude to those who have worked on the show throughout the years.

"It is hard (nearly impossible, actually) to really accepot that this picture of the first of the final 24 episodes we will shoot for The Big Bang Theory," he wrote accompanying an image of the principle cast.

He continued: "I am so terribly grateful for the cast in this picture and the cast members who aren't pictured here- whether they were in one scene or many episodes along the way; you are all my playmates that I have fallen in love with."

Parsons did not address rumors that he was the one who potentially sealed the show's fate.

The star has taken on multiple projects in recent years, including a stint on Broadway in "The Boys in the Band."

The news comes as a shock to fans after CBS Entertainment president Kelly Kahl told reporters at the 2018 Television Critics Association press tour that he didn’t think the smash-hit comedy would end in 2019, despite the cast not yet being signed on to continue.

“We don’t believe it’s the final year. We are in preliminary discussions to renew the show with Warner Bros.,” he said.

Parsons’ co-star Cuoco was among the first to lament the show’s ending in a post on her Instagram.

“No matter when it was going to end, my heart would have always been broken in two,” she wrote.

"The Big Bang Theory," which first premiered in 2007, has earned 52 Emmy nominations and 10 wins during its run. It ranked as TV's top sitcom up until the 2017-2018 season, when the "Roseanne" reboot bumped the comedy to second place.

Fox News’ Mariah Haas contributed to this report.