The actor died in her sleep surrounded by family at her home in Montdurausse, France, her agent told the Associated Press on Friday (23 September).
No cause of death was given.
Born Estelle Louise Fletcher in Birmingham, Alabama in 1934, Fletcher began a career in acting in the 1950s with small roles on television after moving to Los Angeles.
However, after marrying producer Jerry Bick – who she later divorced – in 1960 and having two sons in quick succession, she decided to put her career on hold to be a stay-at-home mother and didn’t work for 11 years.
“I made the choice to stop working, but I didn’t see it as a choice,” she said in a 2004 interview. “I felt compelled to stay at home.”
As a result, Fletcher was little known when she was chosen for the role of Nurse Ratched opposite Jack Nicholson in the 1975 film One Flew Over the Cuckoo’s Nest.
Director Milos Forman had admired her work in Robert Altman’s 1974 film Thieves Like Us.
At the time, Fletcher didn’t know that many other prominent stars, including Anne Bancroft, Ellen Burstyn and Angela Lansbury, had turned down the role of the callous nurse.
“I was the last person cast,” she later recalled. “It wasn’t until we were halfway through shooting that I realised the part had been offered to other actresses who didn’t want to appear so horrible on the screen.”
Fletcher won the Best Actress Oscar for her performance in 1976, telling the audience at the awards ceremony: “It looks as though you all hated me.”
She then addressed her parents, who are both death, simultaneously in speech and sign language. “I want to thank you for teaching me to have a dream,” she said. “You are seeing my dream come true.”
The speech was met with a moment of silence, followed by thunderous applause.
One Flew Over the Cuckoo’s Nest was the first film since 1934 movie It Happened One Night to win the Oscar for Best Picture, Best Director, Best Actor, Best Actress and Best Screenplay.
Fletcher continued to work into the 2010s, with roles in films such as Exorcist II: The Heretic, Mama Dracula, Dead Kids and The Boy Who Could Fly.
She was nominated for Emmys for her guest roles on the TV series Joan of Arcadia and Picket Fences, and had a recurring role as Bajoran religious leader Kai Winn Adami in Star Trek: Deep Space Nine.