Fashion designer Richard Nicoll has died of a suspected heart attack, his family said. He was 39.
The family said the London-born designer died early Friday in Australia, where he lived.
New South Wales police confirmed that officers were preparing a report for the coroner "after a man was found deceased in a unit in Darlinghurst, Sydney" on Friday morning.
Nicoll was raised in Perth, Australia, and studied at London's Central Saint Martins' College. His 2002 graduate collection was purchased by Dolce & Gabbana
He later worked as creative director of Parisian label Cerutti, designed under his own name and for Marc Jacobs at Louis Vuitton and produced collections for Topshop and Fred Perry.
Nicoll's modernist designs have been worn by celebrities including Kylie Minogue, Keira Knightley, Sienna Miller and Julianne Moore.
Nicoll's family said he had been due to start new roles with Adidas and Woolmark.
In a statement, his family called Nicoll "one of the quiet stars of fashion. He was a true gentleman, a wonderful friend and a much-loved son."
Singer Lily Allen tweeted that she was "privileged to have known him and to have worn many of his beautiful creations."
Edwina McCann, editor-in-chief of Vogue Australia, said Nicoll "was an extraordinarily talented designer and a wonderful, warm, generous human being."