Dick Van Dyke is getting quite candid on "Oprah: Where Are They Now?" with how he came to struggle with alcohol abuse.

"I was very shy -- with strangers -- I couldn't talk to people," the 90-year-old entertainment legend admits in ET's exclusive first look at his OWN interview. "And I found if I had a drink, it would loosen me up. The barriers went down and I became very social. That’s what got me started."

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The veteran actor says that his struggle with alcoholism wasn't easy to overcome. "It took me a long time to get over it," he adds.

The 90-year-old actor says he is now using his story of substance abuse to help others overcome similar issues. "I get a lot of letters from people, who say all of a sudden they weren't ashamed to admit they had a drinking problem and they got help," he shares. "So I'm very proud of that."

The season premiere of "Oprah: Where Are They Now?" featuring Van Dyke airs Saturday, Jan. 23, on OWN.

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When ET caught up with Van Dyke in October, he revealed his secrets to staying young. "I've always kept moving, which is the most important thing," he said. "I'm either singing or dancing or something."