Jon Cryer wanted to end Two And A Half Men to save Charlie Sheen's life.
The 57-year-old actor, who starred in the classic sitcom for eight seasons alongside Sheen, reflected on the "crazy firestorm" towards the end of the star's tenure on the show.
He told Entertainment Tonight: "When we started noticing things were getting stranger for him, and his marriage fell apart, he was still lovely to work with, he still showed up on time and knew his lines and was doing the job.
"But you could tell there was that there was some trouble brewing… He started to have issues with the writing and sometimes issues with the writing that I didn’t understand.
"I would say, 'This is the kind of joke you had no problem with a year-and-a-half ago, and suddenly now it's an issue?'
"So, you know, it was very subtle. It took a while before it started really going off the rails."
Eventually, Sheen's behaviour became more unpredictable, and Cryer and the sitcom's creator Chuck Lorre had serious conversations about the future.
He said: "I think, uh, there was a moment where Chuck Lorre and I were looking at each other and we said: 'It's not worth this show going on if going on enables Charlie Sheen to kill himself’.
"'If giving him enough money to do whatever the thing is that ends his life, you know, we don't want to be a part of that'.
"And I think, actually, when Charlie was let go from the show, the first thought amongst most of us was, 'OK, we're done. This has been a great thing but, uh, we're done at this point.' "
Instead, Lorre decided to kill off Sheen's character and instead brought in Ashton Kutcher to replace him.
Cryer added: "He was just so positive every day and just brought so much to the table that we were all a little shell shocked after the Sheen craziness.
"We had forgotten how tense we were all the time we were all waiting for the next shoe to drop. And once Ashton came in with this just incredible positive energy, we all went, 'Oh, this can be fun again!' "