Princess Grace's grandson Pierre Casiraghi becomes ambassador for Dior

A grandson of Princess Grace has become the latest model for fashion house Dior, described as "an icon of elegance".

Pierre Casiraghi, 34, is the youngest son of Princess Caroline of Monaco and Stefano Casiraghi.

His uncle is Monaco's ruler, Prince Albert II and Casiraghi is currently eighth-in-line to the Monegasque throne.

READ MORE: From Spain to Sweden, here's a handy guide to some of Europe's major royal families

It's no surprise Casiraghi has signed with Dior - his wife, Beatrice Borromeo became an ambassador for the French brand in February. She is also the face of high-end Italian jewellery brand Buccellati.

The couple have long been among the most stylish at events in glitzy Monte Carlo, famed for their good looks and of course, royal pedigree.

"An icon of elegance, Pierre Casiraghi becomes Dior's ambassador," Dior announced in a media release.

"The Monegasque businessman embodies the new facet of tailoring constantly reinvented by Kim Jones [creative of Dior's men's line], a timeless modernity."

READ MORE: Princess Charlene of Monaco's best jewellery moments

Casiraghi is also a competitive sailor and took teen climate activist Greta Thunberg from Europe to the United States across the Atlantic on his a carbon neutral monohull racing boat in 2019. He offered his services to Thunberg after she appealed for ways of getting to New York without damaging the planet.

The Monegasque royal family has been linked with Dior since the days of Princess Grace.

The former actress regularly wore its creations, while Casiraghi's aunty Princess Stephanie worked at Dior as an intern under designer Marc Bohan in 1980s.

Casiraghi's mother, Princess Caroline, wore a dress by Bohan for her 1978 wedding to Philippe Junot.

Casiraghi's sister Charlotte became a brand ambassador for Chanel last year, while his cousin Pauline Ducret has her own clothing line, Alter.

In August, Casiraghi's wife was named by Tatler as the most stylish European royal.

The pair are regularly seen at official events with the rest of the royal family, including the annual Rose Ball gala.

The event has been held every year since its creation by Princess Grace in 1954, including in 1982 when she died in a car accident. But it was postponed in 2020 due to the coronavirus pandemic.

Beatrice, who is the daughter of an Italian count and is a former political journalist and documentary maker, married Casiraghi in 2015 in the gardens of the Prince's Palace of Monaco, in front of the who's who of Europe's royal families.

The bride wore four couture dresses throughout her wedding celebrations. For her civil ceremony, Beatrice chose two Valentino gowns.

READ MORE: Why just one of Princess Caroline's children has a royal title

They have two sons, Stefano Ercole Carlo, born in February 2017 and Francesco Carlo Albert, born in May, 2018.

The couple named their first son Stefano, after Pierre's late father who was killed in a speed boat accident in 1990.

In 2016, before she signed with Dior, Beatrice spoke about having to borrow evening gowns for red-carpet events.

"For formal occasions I wear Valentino or Armani because they are kind enough to let me borrow stuff. I couldn't afford to buy as many dresses as I need for public functions," she told Glamour.