She bravely revisited her own personal experiences of anorexia when she slipped into the role of an eating disorder sufferer for new Netflix film To The Bone.

And Lily Collins looked noticeably slimmer when she promoted the movie at a special screening of the film in Los Angeles on Thursday evening after revealing she ‘lost weight safely’ with the help of a nutritionist for the role. 

The outing comes as Lily admitted her friends and family were shocked by her new appearance as she had to tell them it was for the role.

The daughter of musician Phil Collins, 28, wore a burgundy dress and sky-scraper heels for the outing.

Flying the British flag for beauty in America, the Surrey native wore her brunette locks in a poker straight fashion which she scraped off her face with a neat parting.

The actress was joined by her co-star Keanu Reeves who plays the unconventional doctor who is assigned to treat Ellen (Lily) for a severe eating disorder in the movie.

Keanu, 52, looked dapper as he dressed up his plain black tee with a suit jacket and trousers to mark the occasion.

The trailer – released on Tuesday ahead of its premiere on July 14 – shows Ellen performing a string of harmful behaviours including: calorie counting, food restriction and obsessive exercise. 

Lily hired a nutritionist to help her lose weight as safely as possible for her role as an anorexia sufferer.

But the star was shocked when her slender frame was recently met with an unexpected positive reaction.

Speaking to NET-A-PORTER magazine, she said: ‘I was leaving my apartment one day and someone I’ve known for a long time, my mom’s age, said to me, “Oh, wow, look at you!”

‘I tried to explain (that I had lost weight for a role) and she goes, “No! I want to know what you’re doing, you look great!” I got into the car with my mom and said, “This is why the problem exists.”’

Lily explained that it was a risk to remind herself of her own traumatic experiences of suffering with an eating disorder when she took on the role of Ellen.

Speaking on a recent appearance for The Today Show, she said: ‘There’s always going to be that thought of stepping back into the shoes of something that wasn’t positive for you may be painful.

‘But that was so therapeutic for me but also to give to Ellen as the character. I suffered from an eating disorder as a teenager for quite a few years.’

But the rising starlet discussed how she wanted to bring attention to the ‘taboo subject’ as discussed how it is important to talk about eating disorders.

‘This project came along on my desk when I was in the middle of writing my book unfiltered talking about my experiences.

‘It was kinda like the universe saying this is something you need to talk about for yourself but also to bring to the attention of people in general,’ she added.

‘I was playing a character. My experiences with this were a beautiful gift to be able to give to the character.’