L'Wren Scott, a designer and the girlfriend of lead vocalist and co-founder of the Rolling Stones Sir Mick Jagger, has been found dead in her New York City flat, BBC reported Monday.
Police are treating her death as a suicide, although the medical examiner has yet to determine an official cause of death.
A spokesperson for Sir Mick said the singer was "completely shocked and devastated" by Scott's death.
The band is currently on tour in Australia.
Scott, 49, born Luann Bambrough, and Sir Mick began dating in 2001. She began her career as a model in Paris and founded her own fashion label in 2006.
Scott's death comes a month after she cancelled a show at London Fashion Week, saying production delays had left key pieces unready for the show.