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The "Dark Shadows" and "Batman Returns" actress says she became involved with a "very controlling" couple who believed in breatharianism - the ability to live without food and water, instead relying on air and sunlight.
Pfeiffer, today a strict vegan, says the odd couple put her on a diet "nobody can adhere to" and described them as "kind of personal trainers."
"They worked with weights and put
Then one day it clicked.
Pfeiffer says she was "saved" when she was introduced to her first husband, actor Peter Horton, who was researching a role for a film about the Moonies - followers of Rev Moon Sun-myung's Unification Church.
The three-time Oscar-nominated actress says that while she was helping him with research "on this cult" she realized, "I was in one."
Pfeiffer says her aha moment came when "We were talking with an ex-Moonie and he was describing the psychological manipulation and I just clicked."