The twosome were feted at the Neue Galerie, the Lauder family's museum devoted to Austrian and German art. Leonard Lauder, chairman of the board of cosmetics giant Estée Lauder, toasted them in a room of canvases by Gustav Klimt.
"Why are we in this room?" he asked guests, including Gayle King (Oprah Winfrey's B.F.F.), Russell Simmons, Anna Wintour and movie mogul Harvey Weinstein. "Klimt's paintings are all done beautifully and in good taste. And the man to our right [Hilfiger] has great taste, and Dee, to my right, is beautiful .... You have a fabulous life ahead of you."
King – who used to be Hilfiger's neighbor in Greenwich, Conn. – said she was there to wish her friend well. "It's always wonderful when a man speaks so lovingly of his wife-to-be," she told PEOPLE. "I'm just a sucker for that."
Simmons also poked gentle fun at the pronounced height difference between Hilfiger and the statuesque Ocleppo (who was formerly married to the 1980s Italian tennis star Gianni Ocleppo). "She's the perfect fit," he said. "He's ten times taller standing next to her."
Friends FirstHilfiger may be living a fairytale romance right now – but it wasn't love at first sight.
"We met three years ago in St. Tropez," he told PEOPLE. "We were introduced through friends and became friends first for the first year."
Ocleppo added that they initially bonded over shared family values. "We started talking about my older son who has some learning problems in school," she said, wearing a white dress by Giambattista Valli. "[One of his daughters] has some similar trouble. They are both in the spectrum of Autism. That's how we bonded."
She didn't even know that he was the Tommy Hilfiger. "He was just introduced as, 'My friend Tommy," she said. "But I knew that he cared about his kids."