The Big Bang Theory cast felt “blindsided” when Jim Parsons decided that season 12 would be his last. A new book has revealed some previously unknown backstage drama that threatened to derail the beloved sitcom’s final season. Titled The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series and written by Jessica Radloff, the book features the show’s cast members detailing how they found out that the series was coming to a close. Leonard actor Johnny Galecki said he saw some of his castmates “emotionally crumble” when they learned The Big Bang Theory would be cancelled due to its most popular star deciding it was time to move on.

Galecki shared that the shock came as a result of Parsons apparently failing to have a “conversation” with the rest of the cast before he told bosses of his plans to leave. “I just disagreed with how it was handled. We thought we were going into [co-creator] Chuck [Lorre]’s office to talk about renegotiating, and then Chuck tossed the baton to Jim. And Jim was shocked and obviously caught off guard,” he said. As a result, relationships quickly became frosty. Both Penny actress Kaley Cuoco and Galecki almost failed to come to work the following day. And when they eventually did, there weren’t many pleasantries being exchanged.

“Kaley could barely make eye contact with Jim during the run-through, but they got through it,” recalled producer Steven Molaro. However, the tension on set thankfully didn’t last long. “Pretty quickly I saw Kaley and Jim talking between scenes and laughing,” Molaro continued. “They seemed to be able to be around each other and not just want to get into their cars and leave immediately afterwards.” Parsons shared that, eventually, after their initial frustrations, the cast was able to come together and enjoy making the final season.