Mercedes McCambridge lived in San Diego

McCambridge, who was 85, won her best supporting Academy Award in 1949 for her big screen debut in the film All the King's Men.

Other film credits included A Farewell to Arms and Giant.

As well as movie roles she also appeared in TV shows including Cagney and Lacey, Rawhide and Dr Kildare.

McCambridge, who died in San Diego, had a reputation for portraying strong women, playing an enemy of Joan Crawford in 1954 western Johnny Guitar.

It was in 1973 that she was cast as the voice of the possessed child Regan, played by Linda Blair, in The Exorcist.

Linda Blair played the young girl in The Exorcist

She described it as one of the hardest jobs she had done, and was disappointed to discover at a preview screening that she had not been credited.

She reportedly fled the cinema in tears, while director William Friedkin tried to explain there had not been time to add her name.

Actors' union the Screen Actors Guild intervened and forced her inclusion in the credits.

Film work began to dry up in the late 1970s and 80s, but in early 1990s she was offered the role of the grandmother in Neil Simon's play Lost in Yonkers, which she performed 560 times.

Away from acting, McCambridge's life was filled with tragedy.

Her son John Lawrence Fifield murdered his wife and children before killing himself in 1987.