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Phil Donahue and Marlo Thomas attend the “Hillary” New York Premiere

Dimitrios Kambouris/Getty Images

Marlo Thomasis lucky in love.

In an exclusive interview, the actress revealed the secret to keeping her 43-year marriage toPhil Donahuegoing strong.

“I call it the three L’s. Love, listening, and lust,” she told PEOPLE at the Women In Media Foundation’s 48th Annual Gracie Awards Gala on Tuesday. “Those are the three L’s. You have to listen and then you’ll know what the other person is really thinking and going through. You have to love each other. And without lust, you don’t have anything.”

Thomas and the host of The Phil Donahue Show, 87, recently celebrated their 43rd wedding anniversary on May 21.

“He’s the best,” she says. “I’m very lucky,”

As for how the pair marked the special occasion, Thomas says it was a low-key, private evening spent with one another.

“Well, it was just fun just to be alone,” she says. “Sometimes we’ve given parties and done things, but we just felt like this year we wanted to just hang out alone. Go to the theater, go to dinner, walk down the street, just be together. It was great.”

Thomas first met Donahue in 1977 when she was a guest on his popular talk show, which ran for 26 years.

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Marlo Thomas attends the Alliance for Women in Media Foundation’s 48th annual Gracie Awards Gala

To mark their 40th anniversary milestone in 2020, the pair shared marital success secrets from their own four decade union, and advice they gleaned from other long term couples in their book:What Makes a Marriage Last: 40 Celebrated Couples Share with Us the Secrets to a Happy Life.

For the project, the actress and talk-show host spent nine months interviewing celebrity couples whose relationships they’ve admired to find out what works and what doesn’t.

Phil Donahue and Marlo Thomas attend the “Hillary” New York Premiere

“We started to wonder if there really is a secret sauce to a successful marriage. And that’s when we decided to break an ironclad rule of our marriage – for the first time, ever – and decided to work on a project together,” they toldAARP: The Magazine, which had excerpted stories from their book, including tips from couples likeKevin BaconandKyra Sedgwick,ChipandJoanna Gaines, andViola DavisandJulius Tennon.

“As different as these couple’s stories are, they share a common plotline: that of two people joining hands and stepping up to the most challenging, invigorating, inspiring, infuriating, thrilling, terrifying, delightful and heavenly job on earth — making a marriage last,” Thomas and Donahue added.

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Marlo Thomas accepts the Lifetime Achievement Award onstage during the Alliance for Women in Media Foundation’s 48th annual Gracie Awards Gala

On the red carpet ahead of Tuesday’s Gracie Awards in Beverly Hills where Thomas was honored with the Lifetime Achievement Award, she expressed gratitude for the recognition.

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Later accepting her honor, the activist said:

“I am so very, very touched to be here today. I flew in from New York where Phil and I just celebrated our 43rd wedding anniversary, talk about a lifetime achievement, not bad for a girl from Hollywood.”

source: people.com