Police were called to her apartment in the 200 block of 11th Avenue at 10:05 a.m. ET. A medical examiner will determine the official cause of death, but a law enforcement official told The Associated Press that Scott was found hanging from a doorknob by her assistant.
Scott, 47, was a renowned stylist and fashion designer whose clothes were worn by celebrities like Nicole Kidman, Angelina Jolie and Penelope Cruz. She was also romantically linked to the Rolling Stones frontman for more than a decade. Jagger is currently in Australia on tour.
A spokesperson for Mick Jagger told ABC News that the singer is completely shocked and devastated.
ABC News and The Associated Press contributed to this report.
