McCambridge, who died in 2004, told Friedkin she would need to swallow raw eggs to make her voice mucusy, start smoking cigarettes again, and also guzzle booze to get the languid, throaty croak necessary for the demon.
Since she was falling off the wagon to do the job, she had one other request: “She said, ‘I’m going to want these two priest friends of mine to be with me in the soundstage at all times,’” Friedkin recalls, still with an element of disbelief. “So I agreed to all of that.”
McCambridge also performed most of the role while strapped to a chair, since that’s how the character was positioned in the movie — even though she later gave interviews saying that didn’t seem necessary to her.
“I tied her hands behind her back. And she would do the dubbing a line at a time, and often she would ask for more booze and more cigarettes,’” the director said. “What would happen to her voice is you sometimes hear a wheezing sound in addition to the words. That came out of her throat.
“You’ve experienced that when you’ve had a cold, and you have a sore throat and with the cough medicine, your throat will make several different pitches at the same time. That’s what happened with her.”
It was a brutal experience for McCambridge, however. “She’d come off a take and then go to a couch in the back where these two priests were and she would collapse in their arms and burst into tears,” Friedkin said.
Playing the demon pulled up some long-buried ones within herself.