"I've always kept moving, which is the most important thing," Van Dyke told ET when asked about the secret to his youthfulness. "I'm either singing or dancing or something."
His 44-year-old wife Arlene is another secret that’s helped kept Van Dyke in good shape.
"We were friends for a long time before I talked her into marrying me, which was an uphill battle," Van Dyke joked. "She's a great cook -- great everything. And we both dance a lot. I came in the other morning and she was washing dishes with her tap shoes on."
While Van Dyke visits the gym every morning, he's not as strict about his diet once he gets home.
"I eat what I want," Van Dyke said. "I eat like a pint of ice cream every night."
One unhealthy consumption that he has been able to cut out is alcohol. Van Dyke said that drinking used to be a problem but that he overcame it through the power of prayer.
"I went to all the rehab and all that kind of thing," Van Dyke said. "I just said, 'I got to get rid of it. Please take it away.' Slowly it started to make me a little sick, a little dizzy. All of a sudden, I didn't want it anymore, which is wonderful."
Van Dyke has been widely celebrated, having won an Emmy, Tony and GRAMMY, but many people think he should have also won an Academy Award for his role in Mary Poppins. As a matter of fact, the film crew thought he deserved an Oscar so much that they crafted him a special statuette. Watch the video to see the consolation trophy that Van Dyke still keeps in his home today.
Van Dyke's book, Keep Moving: And Other Tips and Truths About Aging, is due out Tuesday.