Diane Keaton is opening up about the "lowest point" of her life: her battle with bulimia when she was in her 20s.

During an appearance on Dr. Oz, the Oscar winner admitted to consuming around 20,000 calories a day when struggling with the eating disorder.

"All I did was feed my hunger. So I was an addict," the 68-year-old told the host. "It was of course the lowest point in my life."

Diane kept the disorder hidden from those around her for four years, she revealed. "I was an obsessed person that somehow tricked myself and managed to hide it. So when you are living with a lie for four years — it wipes out any growth at all whatsoever."

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The actress was finally able to regain control of her life with the help of a therapist. "One day I stopped and I never, ever did it again," the And So It Goes star explained. "I just stopped and I don't know why."

This isn't the first time Diane has talked about her past struggles. She wrote in her 2011 book, Then Again, how relieved she felt to finally get the secret off her chest.

"I have nothing to hide. It's not relevant, but for me it feels good," she wrote. "I think I'm a sister to all the rest of the women — and I'm sure men as well — who have had some kind of eating disorder, and I'm a part of the team."

Diane is currently promoting her new memoir, Let's Just Say It Wasn't Pretty, available now.