Former Growing Pains child star Jeremy Miller gets candid about his addiction to alcohol in a conversation with Oprah Winfrey, revealing he first started drinking when he was only four.

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In a sneak peek from Saturday’s Oprah: Where Are They Now?, Miller, 39, says when he was four, his grandparents “threw a lot of parties and [he] would run around after the parties and finish all the beers.”;

By the time he was 12, he says, he began drinking regularly.

“There was always something there,” Miller explains. “I never had that off switch.”

Watch the full clip below.