Lily Collins feared her eating disorder would stop her from having children.
The 28-year-old actress became anorexic and bulimic during her teenage years, and Lily has admitted the stress she was putting her body through led her to believe she may not be able to have kids of her own.
She shared: "My throat burned and my oesophagus ached. My periods stopped for two years and my life was out of control. I was terrified I had ruined my chances of ever having kids."
Lily, who is the daughter of musician Phil Collins, plays an unruly 20-year-old anorexic girl in the new Marti Noxon-directed drama 'To the Bone'.
And the actress admitted the opportunity to star in the movie arrived at the perfect point in her life.
She told the Daily Mail newspaper: "I'd decided to write a book about my life and, ironically, just as I was starting on the chapter about my eating problems, I was sent the script for 'To The Bone'. It wasn't about me.
"It was a semi-autobiographical film by the American screenwriter and director Marti Noxon about her battle with anorexia. And she had no idea that I'd been through the same thing - not many people did.
"And if that's not a sign from the universe that this is something you need to talk about, I don't know what is. I had already been doing research for my book by reading back in my old journals, looking at old photographs and talking to friends and family about what had happened to me."
And Lily admitted she could see strong parallels between the struggles of her on-screen character and those of her real-life self.
She reflected: "The script rang so true. I thought, 'The person who wrote this really experienced the situation,' and there were definitely some situations I could relate to."