Sir Mick Jagger is said to be "completely shocked and devastated" as tributes were paid to his girlfriend L'Wren Scott who was found dead in a New York apartment.
The 49-year-old model and designer had been dating the Rolling Stones frontman since 2001 following his split from wife Jerry Hall.
Her body was discovered this morning at a property in Manhattan and it is understood that police do not suspect foul play.
A spokesman for Sir Mick said: "He is completely shocked and devastated by the news."
The Rolling Stones had this afternoon flown to Australia ahead of a performance at the Perth Arena, in the west of the country, which had been scheduled to take place on Wednesday.
Two days ago they had played a show at the grand ballroom of Singapore's Marina Bay Sands, rounding off the Asian dates of their 14 On Fire tour.
Scott, who was said to be 6ft 4ins tall and towered at least half a foot over her boyfriend, became well-known in Britain after she got together with Sir Mick.
She designed stage outfits for notable performances at Glastonbury Festival and Hyde Park in recent years. Sir Mick was there to support her when Scott showcased her collection in her debut London fashion show last year.
As news broke of her death, tributes from the world of fashion and showbusiness flooded on to Twitter.
Bianca Jagger, one of Sir Mick's former loves, tweeted: "Heartbroken to learn of the loss of the lovely and talented L'Wren Scott. My thoughts and prayers are with her family. May she rest in peace."
Fashion designer Marc Jacobs wrote: "Rest in peace, L'Wren Scott. You'll forever be missed."
Pop band Duran Duran added: "Such sad news. Our condolences are with L'Wren's family and friends."
Model Daisy Lowe tweeted: "What a loss to the world. Such an inspired woman. She dressed the feminine form unlike any other."
Entertainer Bette Midler wrote: "Just got news of the beautiful L'wren Scott's death perhaps by her own hand. I am devastated. A rare, wonderful, talented soul. Goodbye."
And actress Emmy Rossum tweeted: "So sad to hear of the death of L'Wren Scott. What a beautiful woman and an incredible designer".
Scott, who was originally called Luann Bambrough but changed her name to launch her modelling career in her teens, was brought up in Utah as a Mormon.
She worked in Paris for a number of years, with the likes of Thierry Mugler and Karl Lagerfeld, then went on to return to the US as a stylist. The designer was a wardrobe consultant for films such as Eyes Wide Shut and Ocean's Thirteen.
She met Sir Mick, 70, when she worked as a stylist on a photo shoot. She launched her fashion line in 2006 with fans of her work said to include Sarah Jessica Parker, Nicole Kidman and Michelle Obama, and she has also designed for Banana Republic.
A spokesman for the British Fashion Council said: "We are deeply saddened at the news of L'Wren Scott's tragic death.
"She was an iconic woman who inspired so many, and a designer whose contributions to the fashion industry were both extraordinary and unique.
"She will leave behind an exceptional legacy however we are so incredibly proud to have had her in our midst. At this sad time our thoughts are with her friends and family."
A spokeswoman for New York City Police Department said: "A 49-year-old female was found this morning at 10.05am at 200 11th Avenue. She was unconscious.
"She was pronounced dead on arrival by the emergency medical services. The investigation is ongoing. We are awaiting medical examiners to determine the cause of death."
A spokesman for Scott said tonight: "We confirm the tragic death of L'Wren Scott. At this devastating time for Ms Scott's family and friends, we request that their privacy be respected.
"There will be no further public statement for the time-being."
Accounts filed with Companies House in October show Scott's British company, LS Fashion Ltd, was running at a loss of more than £3.5 million in 2012, up from more than £2.5 million the previous year .
The documents also show the firm owed over a million pounds, despite having assets totalling a similar amount.