"I'd just go for days -- sometimes two or three days straight -- without eating anything at all. It got quite serious, although at the time I didn't recognize it for what it was," described singer Zayn Malik in an extract from his autobiography Zayn, out this week.

Describing his battle with an eating disorder during his time with One Direction, Malik explains that in his final months in the boy band, he was concealing a dark secret.

"The workload and the pace of life on the road put together with the pressures and strains of everything going on within the band had badly affected my eating habits," he explained. "I think it was about control. I didn't feel like I had control over anything else in my life, but food was something I could control, so I did.

Thankfully, the boyfriend of Gigi Hadid now has his eating disorder under control, as well as issues with ADHD and anxiety.

If you or anyone you know is battling with an eating disorder, anxiety or depression contact Reach Out Australia.

Zayn Malik reveals battle with eating disorder