Diane Keaton became bullimic to "fill a vast hole" in her life.
The 'Annie Hall' actress was gripped by the eating disorder in her 20s and didn't even discuss the struggle with her then-partner Woody Allen.
She explained: "I was trying to fill a vast hole. I had a massive appetite for ... everything. Just wanting a lot.
"I can't explain it - I still don't really know why. But I will tell you why I stopped - I went into analysis with a woman five days a week because it was real bad.
"[Did Woody know?] No, not at all. No one knew. I was really good at hiding. But I asked him about an analyst. Maybe he did know, but I don't know for sure.
"I think it came up in a conversation like, 'Maybe I should... Do you know anyone?' that kind of thing."
While she credits her therapist for her recovery, Diane took a year to confide in her.
She added: "I didn't tell my analyst for a year. One day I was lying on my back, not looking at her, and finally I'd had it with myself and just blurted it out and said, 'I'm never going to change ... I'm never going to stop.' She didn't say anything. She just let it pass and then I was able to stop because finally I confessed. I was a genius at hiding."
Though the 71-year-old actress no longer suffers from bulimia, she admits she is still "strange" about her eating habits and the foods she will and won't consume.
She explained to Radio Times magazine: "I quit eating meat and fish, so it's a lot about nuts and cheeses. I do love cheese. It's weird, once you had stopped being bulimic - and it was a habit for three years - you're strange about food."