Imagine sitting at your desk and getting this call:

“We’re making a movie about your life. David O. Russell is directing it, and by the way, Jennifer Lawrence will be playing the role of you.”

In a very abbreviated nutshell, that actually happened to Joy Mangano, 59, the fabulously successful Long Island entrepreneur/inventor and HSN pitchwoman whose rags-to-riches journey started with the invention of a mop. Not just any mop, mind you, but the legendary, self-wringing Miracle Mop.

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On Christmas Day, “Joy,” a movie inspired by her struggles as a divorced, single mother turned mogul by way of that mop, will open at movie theaters across America. Along with Lawrence, it stars Bradley Cooper and Robert De Niro; the movie and Lawrence have both been nominated for Golden Globe awards.

HOW IT CAME TO BE

About a decade ago, HSN honcho Barry Diller, working on a pilot about inventors, invited Mangano to dinner in Los Angeles. Also on the guest list: Ken Mok, a television and film producer. After hearing about her roller-coaster life, Mangano recalls, “Ken said, ‘I’m going to tell your story. It’s amazing.’ ” A few years later, a call came in to Mangano’s company, Ingenious Designs, in Ronkonkoma. “It’s Ken, who tells me my story got into the hands of David O. Russell and they wanted to make the movie,” Mangano says.

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“This can’t be real,” she said at the time, recalls her daughter, Christie Miranne, 33, one of the company’s senior vice presidents. Upon learning that Lawrence would be playing her mom, Miranne says, “I braced myself so I wouldn’t fall on the floor.” As for Mangano, she says Lawrence playing her “made me feel old, number one. But how do you even digest that? That’s so amazing there aren’t even words.”

Mangano and her three children didn’t view “Joy” until the Dec. 13 premiere in Manhattan, though a family outing to see “Trainwreck” included a trailer. It was quite a moment, says Mangano’s son, Bobby Miranne, 32, an executive vice president at the company. After the premiere, Mangano said she was so impressed with Lawrence’s performance and “overwhelmed with emotions . . . I don’t think any of us brought enough tissues!”

A SPECIAL NIGHT AT DE NIRO’S PLACE

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A good portion of the film was shot last winter in Boston, and though the always-busy Mangano was twice scheduled to visit the set, snowstorms made travel impossible. However, family and cast came together one wintry night last year at De Niro’s Greenwich Hotel in TriBeCa. Christie Miranne called the evening “one of those pinch-me-I’m-dreaming moments. It was magical to watch them be so intrigued by Joy’s story. The fireplace was going and there was Robert De Niro sitting in a club chair. . . . He had a presence all of his own.” At one point, Miranne says, “Jennifer grabbed Joy’s hand and said to David, ‘Look at the nails, a French manicure.’ ” (That manicure is a Mangano signature.)

Lawrence revealed that in studying for her part as Joy, she watched recordings of the inventor’s early pitches on HSN, including ones for “Huggable Hangers” and found her so compelling that she wanted to buy them on the spot. Mangano describes the night as “beautiful, everyone was in unison. There is something special when creative people get together.” Mangano’s take on Lawrence? “She’s beyond her years, so brilliant, hysterical and so talented. She’s doing what she should be doing.”

One thing Lawrence will not be doing in the film is a rendition of Mangano’s famously distinct Long Island accent. Promoters of the film are quick to say that it is not a biopic but rather inspired by Joy’s life. Lawrence recently said on “The Tonight Show With Jimmy Fallon” that the movie was “half Joy Mangano’s story and half [Russell’s] imagination and other powerful, strong women who inspired him.”

PHONING IT IN

The director mined much of his Mangano material by phone. Calls would last from dinnertime to 3 a.m. “He knows more about me and my experiences than anyone,” Mangano says. Added bonus to the long talks? “I’ll never need therapy,” Mangano says, laughing.

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One of Mangano’s closest friends, Ronni Fauci, 66, of East Meadow, another VP at Ingenious Designs, was interviewed by Russell for several hours. Fauci, who met Mangano as a young mother in the PTA and says their relationship is “as close as sisters,” is played by Dascha Polanco, who plays Dayanara Diaz on “Orange Is the New Black.” Russell, Fauci said, “wanted to know about Joy’s approach to adversity. It’s over, under, around or through. There’s no situation Joy cannot overcome or circumvent.”

BUSINESS AS USUAL

At a Newsday photo shoot at Mangano’s luxurious but serene 42,000-square-foot mansion on 11 acres in St. James, she seems maybe even more excited about the newly reinvented Miracle Mop than she is about the film. “You don’t have to twist it anymore. You’re going to want to mop your floors,” she says of the product, which she obsesses about keeping at its original price: $19.95. And then, on Jan. 9, there’s a major debut of Joy store-within-stores at Macy’s, Target, The Container Store, and Bed, Bath & Beyond. As for parting advice for the ambitious? “If this movie inspires even just one more person to believe in themselves and to go after their dreams, then it’s made a very special impact in this world. And I think it will!”

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Correction: An earlier version of this story contained an incorrect price for the Miracle Mop.