Shirley MacLaine, 90, Reveals the Secret to Her Longevity — and It's Not About Great Genes! (Exclusive)

The Oscar-winner celebrated her 90th birthday on April 24

<p>Chris Delmas / AFP</p> Shirley MacLaine

Chris Delmas / AFP

Shirley MacLaine

On her 90th birthday, Shirley MacLaine is sharing the surprising secret to her longevity.

MacLaine, who turned 90 on Wednesday, April 24, tells PEOPLE she's living her best life thanks in no small part to her history with dance.

"I started my dance training at age three and stopped at about 67. It taught me discipline, loving music, working with people and dealing with pain," says MacLaine, who got her start on Broadway before hitting it big in Hollywood.

Related: Shirley MacLaine Is 'Feeling Good' as She Turns 90, Teases New Book About Her 'Wonderful Life' (Exclusive)

MacLaine also keeps an attitude of gratitude when it comes to her outlook on life. The star shares that she's grateful "that I can keep working." But she's also counting her blessings in other parts of her life.

"I have my friends and I am really healthy," she says.

MacLaine is gearing up for an exciting year. The actress — who has starred in classic films like The Apartment, Terms of Endearment and Steel Magnolias — is set to begin filming a new movie, People Not Places, in Atlantic City soon.

She's also sharing a look back at her life in photos in her upcoming book The Wall of Life, which will be released on October 22.

<p>Crown</p> 'The Wall of Life' cover


'The Wall of Life' cover

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Related: Shirley MacLaine Says She Has a 'Perfect Life' at 85: 'I Eat What I Want, I Sleep When I Want'

"I have lived a wonderful life and I wanted to share it," MacLaine notes of her book. "All of the photos brought back such wonderful memories.”

Longtime fans of MacLaine will know that her zest for life is nothing new. In 2019, she spoke to PEOPLE as she prepared to turn 85, and revealed that her life was looking pretty beautiful then, too.

“I have what I consider just a perfect life… I eat what I want, I sleep when I want," she said at the time, adding that having animals around helps keep her content as well.

"Learn to amalgamate with nature,” she explained. “I have all the animals around me [in New Mexico]. It’s everything I need to be happy.”

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