When Janelle Monáe first tried on her Oscar frock, a glittery tulle-and-lace confection by Elie Saab, her stylist cried. “It was such a beautiful moment, and I had never seen her in a gown like that, ever,” remembers Maeve Reilly, who’s been outfitting the singer-turned-actress in her trademark black-and-white palette since 2013. “It was spectacular — it took my breath away.”

When Monáe swept into the Academy Awards, the fashion world was also dazzled by her flight of fancy. Vogue hailed the evening’s “most dramatic red-carpet moment,” Twitter lit up with raves and fashion bloggers Tom + Lorenzo wrote, “Dammit, she looks magical.”

Another sartorial score for Lebanon’s best-known couturier, who for decades has dressed Hollywood and real-life royalty (from Nicole Kidman and Gwyneth Paltrow to Queen Rania of Jordan), along with pop stars, supermodels and socialites.

“I feel blessed to have so many beautiful and talented women wearing my designs consistently,” the 52-year-old designer tells Alexa.

Now Saab has set his glamorous sights on the US, and in March opened his first stateside store at 860 Madison Ave.

The marble-lined flagship showcases his ready-to-wear, fragrance and accessories lines, including his new eyewear collection with Safilo and his signature bag, “le 31,” in this season’s star print.

“I am passionate about architecture and interior design,” says the red-carpet master, who hopes to open a bridal shop in New York in the future. “I think it surprises people to learn that I am really a minimalist at heart. This is well reflected in the design of my homes and boutiques, which are very simple and almost Spartan in terms of décor.”

Indeed, Saab is more of a maximalist on the fashion front. His fairy-tale gowns are often adorned with intricate beading and embroidery, or fringed with feathers.

He made Queen Rania’s 1999 embellished coronation ensemble, which she paraded again at a 10-year celebration of her husband’s reign. In 2002, Halle Berry made history when she won an Oscar for Best Actress swathed in his burgundy embroidered-mesh-and-taffeta gown. More recently, Saab has lent shimmer to everyone from Beyoncé to Kendall Jenner.

“About 100 seamstresses work in the haute-couture atelier in Beirut,” says Saab, an autodidact who founded his label at the tender age of 18. “Among them, four have been part of the house for more than 25 years, and 10 for more than 15 years.”

Loyalty is important to the designer, who grew up in war-torn Beirut and lives between the Lebanese capital, Paris and Geneva.

“My wife, Claudine, is my greatest support and has been by my side since the beginning. Her opinion matters a great deal. My family is my strength and is what helps me to go on and aspire for more.” Two of his three sons have already followed him into the business.

But it’s Saab père who drapes the silk tulle and devises the paillette motifs — some 5,000 sequins and 1,000 crystals were hand-stitched onto Look 24 in his 2017 spring couture collection.

“He creates dresses that you remember forever,” says Reilly. “You know you’ve made it as a stylist if you have Elie Saab gowns in your fitting.”