William Costelloe to Carry His Father Paul’s Namesake Label Forward as Creative Director

LONDON — William Costelloe, one of the seven children of Irish designer Paul Costelloe, who created looks for the young Princess Diana, has been named creative director of the Paul Costelloe brand.

In his new role, the younger Costelloe will lead the development of all the brand’s collections, continuing the legacy of his father, who passed away last November at 80 following a short illness.

Prior to that, he worked as design director at the Paul Costelloe brand, overseeing the design and development of catwalk collections and collections for its global retail and license partners.

The brand is set to kick off the fall 2026 edition of London Fashion Week on Feb. 19 with a runway show presenting the first collection designed by William Costelloe.

“My father taught me to see fashion through the eyes of an artist; to respect materials, the process, the people. I am honored to be continuing his legacy, and I approach this role with determination, gratitude, and excitement for what lies ahead for the Paul Costelloe brand,” he said under an Instagram post.

Before joining the family business, William Costelloe honed his craft as a print and textile designer at Portuguese bedding manufacturer Piubelle and homeware producer Matceramica, and as a visual merchandiser and stylist for La Rinascente in Milan.

He received women’s fashion design and textile training at Istituto Marangoni in Milan and holds a bachelor’s degree in painting from Camberwell College of Art and a master’s degree from Chelsea College of Art in London.

Paul Costelloe was part of the wave of Irish designers, including Louise Kennedy, who landed in London in the 1980s, becoming part of the flourishing fashion scene. They would pave the way for names such as John Rocha, Lainey Keogh, and Orla Kiely.

A tall, somewhat gangly Irishman, the elder Costelloe had the native charm of his countrymen with a constant glint in his eye, as if he could not wait to tell a joke — or share in a laugh. He first showed at London Fashion Week in 1984 and quickly became a fixture on the calendar.

He would spin that charm — and his royal connections — into a thriving creative and commercial business, which today offers menswear, accessories, home, jewelry and eyewear collections.

His clothes have always had an Irish practicality and wearability, focusing on materials native to Ireland, such as linen and wool. The collections are made in Italy, at a long-standing manufacturer based in Ancona.

In the early ’80s, one of Princess Diana’s ladies-in-waiting discovered Paul Costelloe’s designs in a shop in Windsor, just outside London, and thought they would suit the young royal.

In 1983, he was appointed as the personal designer to Diana, and she wore his outfits until her death in 1997. Paul Costelloe dressed the princess in polka dots and printed dresses, as well as his signature bold-shouldered jackets.