The Paris Big League Fashionmakers: Anne-Marie Munoz of YSL, Lou Lou Klossowski, Yves St. Laurent and Karl Lagerfeld in front, Pierre Berge and Thadee Klossowski behind

PARIS — Anne-Marie Muñoz, a key figure at Saint Laurent who managed the design studio for four decades, died on Jan. 3 at 87.

Her death was confirmed by the Musée Yves Saint Laurent.

Muñoz, whose full married name was Muñoz-Yagüe, was born under the name Poupard on Feb. 27, 1932 in Bordeaux. At the age of 18, she moved to Paris and her uncle Henri Sauguet, a composer, introduced her to his longtime friend, Christian Dior, who brought her into his house in 1951. She met Yves Saint Laurent in 1955 and the pair became firm friends, forming a tight circle that included Karl Lagerfeld and star model Victoire Doutreleau.

Muñoz worked for a decade at Dior before taking part in the first Yves Saint Laurent collection in January 1962, then moved to the house the following year to work alongside Saint Laurent and Pierre Bergé. She worked at the house until 2002, overseeing the production of more than 150 haute couture and ready-to-wear collections over the years, according to a statement from the Fondation Pierre Bergé-Yves Saint Laurent.

She married José-Maria Muñoz-Yagüe in 1962, and had two children, Carlos and Marie.

Known for her unconventional approach and refined style, Muñoz counted artists among her friends, who included Loulou de la Falaise, Blanca Li and the photographer Martine Barrat.

“Anne Marie Muñoz is as integral to the house of Yves St. Laurent as Pierre Bergé and Saint Laurent himself. Some Parisians contend this darkly beautiful, highly intense and publicity-shy woman is the ‘best-kept secret of French fashion,’” wrote WWD in 1980.

“Muñoz’s home life seems as rich as her working life,” according to the profile, which described her Left Bank Paris apartment — located on the Boulevard Saint Germain — as a setting for “lively dinners, teas and brunches with guests including young painters, writers and their children’s friends,” and decorated with huge vases of flowers and minimalist paintings, as well as drawings by Saint Laurent.

Munoz described her process of translating Saint Laurent’s ideas into action.

“It is a lively dialogue, a strong communication and a creative process that is unique,” she told WWD.

“As he grew, I grew.”