Billy Bob Thornton is offering a candid look at his past substance abuse issues.

On the Nov 20 episode of theAfter Dinner Thinks with Ann Wilsonpodcast, the 70-year-old actor opened up to co-hosts Ann Wilson and Criss Cain about the period when he was doing psychedelics in his early 20s.

“I was a drug addict. I quit drugs when I was 24. I did everything,” Thornton said. “I even was on morphine for a while, ’cause I had a nurse friend.”

The actor added that he “did a lot of psychedelics” during that period: “And what was funny about acid was — I didn’t like it. I didn’t have good trips. And I kept doing it ’cause everybody else was doing it.”

While he didn’t necessarily enjoy the experience in the moment, theLandmanstar said that he believes his experiences with psychedelics did have some benefits. “I do believe it did unlock my mind to be a better artist,” he said. “I honestly believe that psychedelics helped me as a writer and as an artist in general.”

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He continued, “It’s so funny to think about those days, ’cause it almost seems like another person to me. But I think it still resonates, and the residue of it is still around. And I’m not sure Paul McCartney and John Lennon were wrong when they said doing acid and opening their minds up did help them with whatever (song) it was.”

Thornton was referring to the accidental acid trip Lennon embarked on during a recording session for “Getting Better” in 1967, which, after ruining the chances of a recording session, prompted McCartney to bring him back to his house and take acid with him.

Thornton was also candid during the episode about how he got clean after his drug addiction.

“I’m glad I quit when I did,” he said. “Because I was this skinny little long-haired hippie, working as a roadie, and I looked in the mirror on an airstream trailer one day and said, ‘You’re gonna die. You have to stop.’ ”

“Back then they didn’t have programs and support groups and things like that,” he said, adding that there was “absolutely” shame around addiction, as Wilson, 75, suggested.

“I quit on my own,” Thornton revealed. “I sweated it out for about four days.”

If you or someone you know is struggling with substance abuse, please contact the SAMHSA helpline at 1-800-662-HELP.