Lily Collins says 'To the Bone' represented a "form of recovery" from her eating disorder.
The 28-year-old actress developed anorexia and bulimia during her teenage years, and has admitted she's benefited from the experience of playing a 20-year-old anorexic girl called Ellen in the new Marti Noxon-directed movie.
She shared: "It was a new form of recovery for me. I got to experience it as my character, Ellen, but also as Lily.
"I was terrified that doing the movie would take me backwards, but I had to remind myself that they hired me to tell a story, not to be a certain weight.
"In the end, it was a gift to be able to step back into shoes I had once worn, but from a more mature place."
Lily also revealed her darkest day on set came when she had to strip off and have her photograph taken by her on-screen stepmother, played by Carrie Preston.
Recalling the specific scene, Lily told the Daily Mail newspaper: "I didn't realise she would really photograph me on her iPhone, but she did. Then she showed it to me and said: 'This is what you look like. Do you think this is beautiful?'
"I was shocked by how I looked. It was a moment that resonated a lot, not just as my character but as me, because I was actually seeing myself."
And Lily insisted she's now finally let go of the desire to feel "perfect".
She explained: "From a young age I've had a desire to put forward this perfect image, whatever perfect was. So even though there was all this un-prettiness going on inside me, I wanted to make sure that my appearance and composure were a certain way .
"Now I feel like I'm starting with a clean slate, so when I take a role I can let go more."
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