Lily Collins has previously opened up about her secret eating disorder battle.

And on Saturday, the 30-year-old revealed that it was her father's separation from her third wife Orianne Cevey that was the catalyst for her illness.

'My life felt out of control. I couldn't handle the pain and confusion surrounding my dad's divorce,' Lily wrote in her book.

'I couldn't handle the pain': Lily Collins (pictured) has blamed her father's divorce for her eating disorder and diet pill abuse

'I was having a hard time balancing being a teenager with pursuing two different grown-up careers - both of which I'd chosen myself but focused heavily on how I looked,' she added.

She revealed that she began starving herself, abusing diet pills and laxatives and exercising obsessively, which all continued into her twenties.

It comes after Lily, who stars in To The Bone about an anorexia patient, revealed she was left terrified that she almost 'ruined her chances of having kids' while she was battling the insidious disease.

'My life felt out of control. I couldn't handle the pain and confusion surrounding my dad's divorce,' Lily wrote in her book. Pictured: Phil Collins and his ex-wife Orianne Collins

Outing: Lily was seen out in Beverly Hills with a pal on Friday

Casual chic: The actress donned a beige blazer over a floral dress

Lily revealed she gorged on 'every type of junk food possible', later forcing herself to throw up, causing her hair to fall out and her nails to become brittle.

Even after the extreme effects of the eating disorder began to show, the daughter of musician Phil Collins continued to starve herself and exercise obsessively.

In her 2017 memoir Unfiltered: No Shame, No Regrets, Just Me, she wrote: 'My hair and nails became brittle.

Eating disorder: 'I was having a hard time balancing being a teenager with pursuing two different grown-up careers - both of which I'd chosen myself but focused heavily on how I looked,' Lily said. Pictured: Phil Collins (far right) with (L-R) his wife, Orianne; son, Nicholas, and daughter, Lily

'My throat burnt and my oesophagus ached. My period stopped for a couple of years. I was terrified I had ruined by chances of having kids.

'I was convinced that I had f***ed myself up beyond repair.'

In her memoir, Lily traced the beginnings of her anorexia back to her father's divorce from her stepmother and the 'terrible disconnect' that grew between them as she got older.

She said the 'terrible disconnect' that grew between them as she got older was the main reason for her eating disorder.

She said: 'Many of my deepest insecurities stem from these issues with my dad.'