Jon Cryer has been through it all in Hollywood and now he's coming out with a new tell-all, spilling lurid details on the Charlie Sheen meltdown and his own love life.
"In the first few years of the show Charlie was sober and he was married to Denise," Cryer tells ET's new correspondent Cameron Mathison. "He was an incredible coworker. That's what made the meltdown all the more scary."
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Cryer pin-pointed the exact moment when he grew concerned for his former Two and a Half Men co-star.
"I think for me the big indicator was getting arrested in Colorado," Cryer recalls. "When that happened, I knew he was no longer sober."
That arrest was in 2009 for domestic violence against Sheen's then-wife Brooke Mueller for which he pleaded guilty.
Things didn't work out for Sheen on Two and a Half Men (his character was killed off the series after taking a few verbal jabs at executive producer Chuck Lorre) after he decided that the sober life "was not the life he wanted anymore."
Ashton Kutcher then joined the show in Sheen's absence. One thing fans may not know about Cryer's past is that 30 years ago he dated Demi Moore -- the two starred together in 1984's No Small Affair -- who would later go on to marry Kutcher.
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"It was awkward in that I'm not sure she even told him that we dated," Cryer remembers. "In our first meeting, we're trying to have that let's-create-that-chemistry meeting and the whole time I'm looking at him, waiting for him to drop the bomb."
There is one detail in the memoir Cryer certainly doesn't want his 14-year-old son, Charlie, to read. After his 2004 divorce from Sarah Trigger, the actor hired a prostitute.
"I went through a divorce, you know," he says. "It's not the proudest moment of my life."
Once the story went public in a excerpt published by The Hollywood Reporter, he had some explaining to do to his son.
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"I found myself picking my son up at school and having to give him a heads up that, 'Oh, you might read something on the Internet today that's a little curious,'" Cryer says. "So I told him the facts of it, and he said, 'Yeah, I'm not surprised.' I was like, 'Wow, okay!'"
Cryer's book So That Happened is in stores tomorrow.