Lily Collins was ''nervous'' about losing weight for her new movie as she has battled an eating disorder in the past.

The 28-year-old actress - who struggled with her weight as a young girl - had to drop a dress size for her role in 'To The Bone' and was ''closely supervised'' by producers and a nutritionist throughout filming.

Speaking on ITV's Lorraine, she said: ''I was nervous right away with the subject matter, but I knew it was for a greater purpose. I'm older now and I have a different perspective on it.

''I was excited to be able to tell this story and open up the conversation for men and women around the world.

''I was kept under close supervision by the producers, the directors, the writer, my mother and also a nutritionist. We worked very closely together, very healthfully.''

Meanwhile, Lily previously revealed the importance of opening about her own struggles to raise awareness to others about the effects eating disorders can have on people.

Speaking about 'To The Bone', she explained: ''This movie was really important to me to be a part of because, as a teenager, I suffered from eating disorders. This is the first time I'm talking about it. This is my moment of talking about it. It's important.

''It's really important. It's something that a lot of young women go through and there's no shame in it, and this movie is about that - it's about embracing your past and about realising it's something that doesn't define who you are, but it's about your experiences, surrounding yourself with people that support you, and about surviving and getting through it.''

And Lily admitted she feared her eating disorder would leave her infertile.

She wrote in her autobiography: ''My hair and nails became brittle. My throat burnt and my oesophagus ached. My period stopped for a couple of years. I was terrified I had ruined my chances of having kids. I was convinced that I had f***ed myself up beyond repair.''