By Agence France-Presse
The announcement came just weeks after the man known as the "Kaiser" in the industry did not appear at shows during Paris Haute Couture week for Chanel, which he had led since 1983.
Just last week, his own fashion line Karl Lagerfeld was still announcing new design collaborations.
German-born Lagerfeld was artistic director of three separate brands, Italy's Fendi, France's Chanel -- the world's richest label -- and his eponymous line.
With his powdered white pony tail, black sunglasses and starched high-collared white shirts, the great friend and rival of Yves Saint Laurent was as instantly recognisable as his celebrity clients.
News of his death is likely to create an outpouring of emotion in the industry, and tributes began flowing in from politicians and fans.
"Karl Lagerfeld is an immense personality, someone out of the ordinary," French Interior Minister Christophe Castaner told RTL radio.