Ivana Trump, In and Out of the Spotlight

“Could be between Ivanka and Eric,” Ms. Serota said. “Maybe Eric now, because Eric is here and Ivanka is in Washington.”

As far as geography goes, Ms. Trump made clear at the diet event that she had a fondness for Europe. The low-calorie, low-carbohydrate plan is the creation of an Italian, and she said she liked “Italian men, Italian food, Italian mountains, Italian sea, everything Italian.”

Last month she was on the Italian version of “Dancing with the Stars” with her fourth ex-husband, Rossano Rubicondi, who was born in Rome. (They married in 2008 and divorced the following year.)

“I had to dance two-minute waltz,” she told the crowd at the diet event. Never mind that just last year, after Marla Maples, the second Mrs. Trump, appeared on “Dancing with the Stars,” Ivana Trump wrote, “What a disgrace that was! No class!” She said she had said no to repeated offers to be a contestant.

But, about what happened after she said yes in Italy. “Now, I had a two-hour rehearsal and then I went live in front of 10 million Italians. And you had to remember the steps, and long dress and long hair and makeup and high heels.” She called it “one of the hardest things I’d ever done.”

She said this as she glided through the Oak Room of the Plaza Hotel, a New York icon that, as she noted, she used to preside over. (Donald J. Trump bought it in 1988 and was forced to sell it, along with other holdings, in 1995.) “I used to be Eloise of the Plaza,” she said, “running through the corridors, through the kitchens, through the ballrooms, through the meeting rooms.”