Published Tuesday, 18 March 2014
The body of the 49-year-old was found unconscious in her Manhattan, New York apartment, but was later declared dead by emergency services.
It is understood that police are treating the death as suicide.
A report in the New York Post suggested the Rolling Stones frontman had ended the relationship before the tragedy.
However Jagger's representative has dismissed the rumours in a statement that read: "The story in the New York Post re [sic] a split between Mick Jagger and L'Wren Scott is 100 per cent untrue. There is absolutely no basis in fact to this story. It is a horrible and inaccurate piece of gossip during this very tragic time for Mick."
Jagger, who has been dating Scott since 2001, was in Australia for the Rolling Stones' tour Down Under when she passed away.
The band arrived in Perth on Sunday, but have now announced their show in the city, scheduled for Wednesday, has been cancelled.
As news broke of Scott's 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."
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."