Anita Pallenberg - actress, model, and longtime partner of legendary Rolling Stones guitarist Keith Richards - has passed away at 73.
Her death was announced Tuesday evening by close friend Stella Schnabel.
No cause of death was stated.
Schnabel paid tribute to Pallenberg in a heartfelt Instagram post:
"I have never met a woman quite like you Anita. I don't think there is anybody in this universe like you. No one has ever understood me so well."
"You showed about life and myself and how to grow and become and exist with it all. I was a little girl thinking I was big but I became a woman through knowing you."
"The greatest woman I have ever known. Thank you for the most important lessons - because they are ever changing and definitive. Like you. We are all singing for you, how you liked it. Go in peace my Roman mother, you will always be in my heart."
Pallenberg found early success as a model and actress (she appeared alongside Mick Jagger in the 1970 cult classic Performance), but it was her personal and artistic involvement with the Rolling Stones for which she's best remembered.
After sneaking backstage at a Stones concert in 1965, Pallenberg kicked off a tumultuous relationship with band co-founder Brian Jones.
When she and Jones parted ways, Pallenberg became involved with Richards, beginning a romance that would last for 22 years and yield three children.
During her time with Richards, Pallenberg enjoyed such creative clout among the Stones that some of the band's best known recordings were remixed at her suggestion.
Pallenberg is credited as a background singer on the band's 1968 classic "Sympathy For the Devil."
Richards' years with Pallenberg were among the most turbulent of his famously wild life.
In his 2010 memoir, the rock icon stated that he and Pallenberg endured a "descent into hell” together, each becoming addicted to heroin during their relationship.
"I like a high-spirited woman. And with Anita, you knew you were taking on a valkyrie — she who decides who dies in battle," Richards wrote in the book.
Pallenberg is survived by Marlon and Angela, her two children with Richards.
The couple had another son, Tara, who died from Sudden Infant Death Syndrome in 1976.