Jim Parsons gets tearful explaining why he quit 'The Big Bang Theory'

Jim Parsons says a "moment of clarity" during a particularly chaotic summer forced him to realize it was time to leave "The Big Bang Theory."

The 47-year-old actor, who played Sheldon Cooper on the CBS sitcom, cried while opening up about his decision to exit the show after 12 seasons during a chat on "David Tennant Does a Podcast With ..."

The "Hollywood" star had "suspicion in my heart" that his two-year contract for seasons 11 and 12 of the show would turn out to be his last. "It was a complicated road, as you can imagine," he said of the decision.

But it was the "very intense summer" between the two seasons that led him to make up his mind for sure.

Just one day after wrapping season 11, Parsons flew to New York City to rehearse for his starring role in "Boys in the Band" on Broadway. The play went into previews less than a week later. The following Sunday, Parsons finally got a day off — but he was forced to spend it shooting a commercial.

"I had a contract with Intel and so I'd scheduled that," he said. "I was exhausted."

Image: The Re-Entry Minimization (Michael Yarish/Warner Bros.)
Image: The Re-Entry Minimization (Michael Yarish/Warner Bros.)

On top of his frantic work schedule, Parsons was devastated about the declining health of the 14-year-old dog he shared with husband Todd Spiewak.

"I'll never forget that walk around the park to let him go to the bathroom before we went to the commercial shoot," Parsons tearfully recalled. "He just looked so bad and I was so tired and Todd was like, 'We've got to go. We've scheduled this. They fit everything around your schedule.' And I just started crying."

"It makes me upset now. I was like, 'This dog's gonna die while I'm off working. I feel so bad,'" he added.

"So I went and did the commercial, I came back, and then Monday I went to do the play and (the dog) had a really bad seizure that night, so I knew that we had to make a decision," he said. The following day, he and and Spiewak made the difficult decision to euthanize their dog.

"It really upset me. Still does," the actor shared, choking up again.

Parsons knew he had to get through six more Broadway performances before his next day off. "I kept thinking, 'I don't know how I'm going to get to the end of this performance.' I was just so beaten down," he said. "But I did."

Unfortunately, he experienced a painful mishap after the Saturday matinee. "I walked out for curtain call and I slipped and I broke my foot," he said.

"It was the scariest moment for the next couple of days because ... I felt like I was at the edge of a cliff and I was teetering and I saw something really dark below," he recalled.

The whirlwind of emotional events caused the actor to rethink the pace of his life.

"I had this moment of clarity — that I think you're very fortunate to get in a lot of ways — of going, 'Don't keep speeding by... Use this time to take a look around,'" he recalled, choking back tears again. "And I did. I was like, 'I gotta make a move.'"

He also thought of his late father, who died in his early 50s.

"My dad had passed years before, but he was 52. And I realized that at the end of season 12 I would be 46," he said. "I'm not superstitious or anything like that. It was just a context thing."

Once he returned to Los Angeles, Parsons told "Big Bang Theory" creator Chuck Lorre and writer Steve Molaro that the 12th season of the show would be his last.

"I said, 'If you told me that like my father I had six years left to live, I think there's other things I need to try and do. I don't know what they are, but I can tell that I need to try,'" said Parsons.