Matthew Perry is telling his story.

In a new clip previewing a longer interview with Diane Sawyer, the Friends star, 53, says one of his castmates, in particular, helped him in his addiction struggles.

During the interview, which airs in full Oct. 28 on ABC, Sawyer highlights sections of the actor's upcoming memoir Friends, Lovers and the Big Terrible Thing, specifically how his former sitcom costars reacted to his addiction.

Sawyer recounts a moment in the book when Perry reveals that it was Jennifer Aniston who initially confronted him. At the time, the actress told Perry, who played fan-favorite Chandler Bing, that she and the others knew he had a problem.

"Jennifer, she says, 'We know you're drinking,'" Sawyer prompted him in the interview clip.

"Yeah, imagine how scary a moment that was," Perry replied.

He elaborated that Aniston, 53, stayed in close contact with him during the pits of his addiction struggle.

"She was the one that reached out the most. You know, I'm really grateful to her for that," he told Sawyer.

The two-minute clip also highlighted other parts of the interview, including details of Perry's "55 Vicodin a day" habit.

"I should have been the toast of the town, but I was in a dark room meeting with nothing but drug dealers and completely alone," he told Sawyer of his Hollywood heyday.

Perry explained that he wanted to speak out now because it was important to him to "do something that would help people."

"Secrets kill you. Secrets kill people like me," he explained.

The 17 Again star recently talked to PEOPLE about his addiction, recovery and telling his story in his new memoir.

"I thought being funny all the time was how I would get through," he says. "I thought [Friends] was going to fix everything. It didn't."

"They were understanding, and they were patient," he said of the whole Friends cast rallying around him then.

"It's like penguins. In nature, when one is sick or very injured, the other penguins surround it and prop it up and walk around until that penguin can walk on its own. And that's kind of what the cast did for me."

The friendships he made with the cast have proven to be lifelong, which was evident when they came together for the 2021 HBO Max reunion show.