Clare Waight Keller becomes the French house’s first female couturier, suggesting a new Golden Age for women in fashion.
The British designer is to show her first collection in October, and oversee all product lines, including men’s.
The music and fashion impresario is the first man to appear in such a campaign for the house.
The French brand is touting a new handbag model, its first new fragrance pillar in 15 years, along with campaigns about the founder.
Georgina Brandolini organized the event, which drew guests including Jason Basmajian and Becca Cason Thrash.
Executives were reluctant to surmise how the family may help or hurt fashion sales.
The designer is to show his debut collection for the French house in Paris.
Industry sources say the revamped and expanded site is slated to launch mid-year.
The music star is to front the new Gabrielle style alongside Kristen Stewart, Cara Delevingne and Caroline de Maigret.