Washington: Her passing occurred in her sleep due to complications from diabetes, as confirmed by The Hollywood Reporter.
Duvall, recognized for her unique screen presence and collaborations with director Robert Altman, had a distinguished career that included notable roles in 'Nashville', 'Popeye', and '3 Women'.
She won the Best Actress award at the Cannes Film Festival for her remarkable performance in '3 Women,' showcasing her extraordinary talent.
Dan Gilroy, her life partner since 1989, expressed his sorrow, stating, "My dear, sweet, wonderful life partner and friend left us. Too much suffering lately, now she's free. Fly away, beautiful Shelley," according to a statement obtained by The Hollywood Reporter.
The actress faced significant personal challenges in recent years.
In a 2016 appearance on 'Dr Phil', she revealed her struggles with mental health, stating, "I am very sick. I need help," as per The Hollywood Reporter.
Duvall was born in Fort Worth, Texas, on July 7, 1949. Her rise to fame began after she was discovered while attending junior college in Houston, leading to her first role in 'Brewster McCloud' (1970).
Throughout her career, she became known for her collaboration with Altman, who provided her with diverse and challenging roles.
Reflecting on her relationship with Altman, she once noted, "He offers me damn good roles. None of them have been alike."
One of her most memorable performances came in Stanley Kubrick's 'The Shining', where she portrayed Wendy Torrance, a woman trapped in a nightmarish situation with her husband, played by Jack Nicholson.
The filming process was grueling, with Duvall later stating, "I will never give that much again."
Reports obtained by The Hollywood Reporter indicated she performed one iconic scene an exhausting 127 times.
Beyond acting, Duvall also made significant contributions to children's programming.
She produced the acclaimed series 'Faerie Tale Theatre' and 'Tall Tales & Legends', both of which featured star-studded casts and received critical acclaim.
Duvall's legacy extends beyond her film roles; she remains a beloved figure in both cinema and children's television.
She is survived by her three brothers, Scott, Stewart, and Shane.