The erratic actor has boasted of "banging seven gram rocks" of cocaine before being fired from the sitcom because of his personal problems, and Jon admits he was always concerned about his health.
Speaking on 'The Ellen Degeneres Show', he said: "Mostly I was worried that Charlie was going to die. That was the big fear for me. And that did not occur and I'm thrilled about that."
In the lead up to being axed from 'Two and a Half Men' Charlie publically criticized the show's creator Chuck Lorre, but also Jon in the mistaken belief that he had "betrayed" him.
He said: "Jon has not called me. He's a Turncoat, a traitor, a troll. Like I said you're with me, or you're with the trolls. Obviously he's with the trolls."
While Charlie has since retracted his comments and made a "half apology", he has yet to speak to his friend personally.
Jon revealed: "We have not spoken. And I will accept an apology both public and private. But again, it was in the heat of the moment, I imagine, when he said it. So I did not put a whole lot of credence in it at the time."
'Two and a Half Men' has continued with Jon and co star Angus T. Jones reprising their roles as Alan Harper and Jake Harper, but with Ashton Kutcher replacing Charlie, whose character Charlie Harper has been killed off.
The first episode in the show's ninth series is set to air later this month.
This hyperactive adventure may keep children giggling at the sheer chaos on screen, but it'll...
Pop quiz. You're Eddie Murphy, a popular comedian who makes about a decade of...
Who would have thought that the life of Jon Cryer -- actor in such memorable...