(CNN) Matthew Perry is continuing to share candid moments from his long journey to sobriety and the struggles he endured during his run on NBC's "Friends" while yoyo-ing between addictions to Vicodin and alcohol.
In an excerpt from his new book "Friends, Lovers and the Big Terrible Thing," Perry recounts how a visit from costar Jennifer Aniston to his trailer made him realize that his secret behavior when it came to alcohol wasn't so secret.
"'I know you're drinking,' she said," Perry, now 53, writes in the memoir, in an excerpt published by the Times of London.
"I had long since gotten over her -- ever since she started dating Brad Pitt, I was fine -- and had worked out exactly how long to look at her without it being awkward, but still, to be confronted by Jennifer Aniston was devastating. And I was confused," he continued.
"'How can you tell?' I said. I never worked drunk. 'I've been trying to hide it . . .'"
Elsewhere in the excerpt, Perry mentioned how he "never" worked high or drunk (although he "certainly worked hungover"), and he said he was largely able to function as part of the uber-successful "Friends" ensemble thanks to his castmates and how they would "group around [him] and prop [him] up" like an injured penguin being supported by the other penguins.
"I was the injured penguin, but I was determined to not let these wonderful people, and this show, down," he wrote.
But that day in Perry's trailer, Aniston told him plainly that he wasn't getting away with anything.
"'We can smell it,' she said, in a kind of weird but loving way, and the plural 'we' hit me like a sledgehammer," Perry wrote.
"'I know I'm drinking too much,' I said, 'but I don't exactly know what to do about it.'"
The "Whole Nine Yards" star also describes in the new book how his weight fluctuated wildly due to the pills making him sick and alleviating his appetite, or alcohol causing him to be bloated.
"You can track the trajectory of my addiction if you gauge my weight from season to season -- when I'm carrying weight, it's alcohol; when I'm skinny, it's pills. When I have a goatee, it's lots of pills."
Perry even referenced specific points in the hit show's 10-season run and clued readers in to what was going on with his addiction at that time.
"By the end of season three, I was spending most of my time figuring out how to get 55 Vicodin a day -- I had to have 55 every day, otherwise I'd get so sick. It was a full-time job: making calls, seeing doctors, faking migraines, finding crooked nurses who would give me what I needed," Perry wrote.
The actor recently said he is finally ready to share his experiences now that he is safely on the other side of addiction.
"I wanted to share when I was safe from going into the dark side of everything again," Perry told People of the book. "I had to wait until I was pretty safely sober -- and away from the active disease of alcoholism and addiction -- to write it all down. And the main thing was, I was pretty certain that it would help people."
"Friends, Lovers and the Big Terrible Thing," by Matthew Perry, will be published by Headline on November 1.