PARIS -- When you think of the Grimaldi girls of Monaco, you think of Caroline and Stephanie, the young princesses whose preternatural beauty, jet-setting ways and tabloid-ready romances long made them paparazzi favorites.
So it comes as a shock to learn they are now middle-age women, with Caroline actually older than their mother, Princess Grace, was when she died in a car accident at age 52.
Now the spotlight is falling on a third generation of Grimaldis, most notably on Charlotte Casiraghi, the 25-year-old daughter of Caroline and her second husband, Stephano Casiraghi, a young Italian businessman who died in a speedboat accident when Charlotte was 4.
To flee the relentless eye of the public and the press, Caroline whisked Charlotte and her two siblings off to a sheltered life, first to a country house in southern France, then to Fontainebleau, near Paris, when Caroline remarried.
Over the years, Charlotte showed up on the paparazzi radar screen episodically. Like the time a survey declared her one of the most eligible young women in the world -- when she was only 16.
Now she is coming out in a different and very public way: by posing for the fashion cameras. Last fall, Vogue France featured her on its cover, with a 24-page fashion shoot inside. She wore Cartier diamond earrings, suede Louboutin pumps and clothes by Dior, Chanel and Celine, among others.
This year, she made her debut as the new face of Gucci, in an ambitious advertising campaign that celebrates her passion for competitive show jumping.
Charlotte "not only embodies the beauty and the grace of the equestrian, but is also a wonderful ambassador for the sport," Frida Giannini, Gucci's creative director, said when the campaign began.
Ms. Casiraghi's work seems linked to a desire to create her own identity and assert her independence from Monaco, a Mediterranean tax haven a little more than half the size of Central Park.
"She has an opportunity to step out into real life and say, 'Oh, I'm here!' " said Peter Lindbergh, who photographed Ms. Casiraghi for the Gucci campaign and has known her and her family for years. "It was a big decision for her, to get out of the house and get involved with advertising."
Just don't call her a model. "Protagonist" is the word Gucci uses to define Ms. Casiraghi's role in its campaign, titled "Forever Now."
Ms. Casiraghi insists she is promoting only the Gucci "spirit," not Gucci products.
"I've always refused to associate myself with a brand," she told French Elle. The ad campaign "pays homage to the Gucci spirit, to 90 years of the history of the house, to our common passion for horsemanship. I do not represent any product or any collection."
Her life could have turned out differently. She could have stayed in Monaco as an accessory to the court of her uncle Prince Albert II. Even though she is not a princess, she is fourth in line to the princely throne.
"I'm not a princess," she told French Vogue. "My mother is, not I. I am the niece of a head of state. And with this status, I have some representational duties, nothing very constraining or very exceptional."
As a student, she was considered gifted but failed to make it into the Ecole Normale Superieure, one of France's elite grandes ecoles. She studied philosophy at the Sorbonne instead.
She evolved into a competitive equestrian and a lover of expensive clothes and has dabbled in writing, editing and videography. She lives much of the time in Paris. She rarely talks to the press, and when she does, access is brief. (She declined through her representatives to be interviewed for this article.)
She appears only occasionally at official events in Monaco, and when she does, she glows. With her full lips, sultry eyes and loose, long chestnut hair that whips across her face in the wind, she is strikingly beautiful.
The Gucci ad campaign builds on a long and comfortable relationship the fashion house has with her family. Princess Grace (who, as Grace Kelly, modeled briefly in New York before becoming an Oscar-winning actress and a princess) was one of its most important clients. Gucci even made a scarf for her, called the Flora. Caroline also wears Gucci from time to time.
As for Ms. Casiraghi, Mr. Giannini, the Gucci creative director, has designed an equestrian wardrobe for her for the past three years. The company has also sponsored her equestrian activities, although the amount of support has not been made public.
According to Stephane Bern, the French celebrity journalist who has covered the principality and its first family for years, Ms. Casiraghi offered to participate in the campaign because she needed money to support her horses.
"She has absolutely no interest in being a model; she's much too intelligent for that," Ms. Bern said. "But competing in horse competitions costs a lot of money. You have to transport your horses one day to Dubai, the next day to Spain, pay for their care, the trainer. Gucci helps by writing checks with lots of zeros."
Ms. Casiraghi's new partnership with the brand expands their relationship. She has already posed for Mr. Lindbergh, whose images focus on the red- and green-striped Gucci webbing. She resisted dressing in all-Gucci, and she pushed to wear her own crimson-red vintage Gucci jacket.
She will pose for three other famous photographers in celebrating other symbols of Gucci's horse-loving spirit. (Next comes the Gucci bit for horses.)