Actress Mercedes McCambridge, who provided the voice of the demon, insisted on swallowing raw eggs and chain smoking to alter her vocalizations. The actress, who had had problems with alcohol abuse in the past, furthermore wanted to drink whiskey as she knew alcohol would distort her voice even more, and create the crazed state of mind of the character. As she was giving up sobriety, she insisted that her priest be present to counsel her during the recording process. At William Friedkin's direction, McCambridge was also bound to a chair with pieces of a torn sheet at her neck, arms, wrists, legs and feet to get a more realistic sound of the demon struggling against its restraints. McCambridge later recalled the experience as one of horrific rage, while Friedkin admitted that her performance--as well as the extremes which the actress put herself through to gain authenticity--terrifies the director to this day.

Film

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