The 51-year-old US star first revealed that he was "molested" as a child in 2020, and Shepard has now confirmed he'll be candid about his painful experiences in his upcoming memoir.
"I have for years on here been acknowledging that I had been molested, and that was its own hurdle to just say that," the movie star said on his Armchair Expert podcast:.
"And I got quite comfortable being able to say that. That was fine.
"Now I'm writing a memoir, and last year really the whole year was about, do I have the balls to write down the details of this?
"Because the details were always gonna be mine. I didn't want anyone to be envisioning me. It's weird that that was still some wall between my shame."
Shepard - who has daughters Lincoln, 12, and Delta, 11, with wife Kristen Bell - admits that it was tough to revisit his experiences for the book.
"I bet it took me four months to tell that story. And when I'm writing it, I cannot help but thinking of people knowing this about me and how still exposed that feels," he said.
"And I was pretty emotional during the few months. I was having really weird, kind of, spikes of emotions and moodiness, and I would forget that's why I was having that.
"But I finished it, and something about it existing there feels like a lot of weight is off my shoulders."
Shepard previously linked his childhood troubles to his addiction problems.
The actor - who battled drug and alcohol addictions - told The Jason Ellis Show: "If you've been molested, you only have a 20 per cent chance of not being an addict. And I was like, 'Hm, interesting,' because in my mind I just like to have a f***ing great time. But when you hear a statistic like that, I'm like, 'Oh no, I was going to be an addict, period.'"
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