Demi Lovato says her body issues began when she was three. The X Factor judge - who has spent time in rehab getting treatment for her eating disorder and self harming - admits she felt she was overweight from a very young age, and the insecurities have stayed with her.

"I remember being three years old in a diaper and rubbing my hand over my stomach ... and I remember thinking in my head, 'I wonder if one day this will ever be flat?'" she said on Katie.

The 20-year-old beauty - who has recently been named as the new ambassador of an anti-bullying campaign - was targeted at school as the girls used to tease her for her appearance. "It played more of a toll on me than if I was physically abused in school. I've always said I wished that they had just hit me in the face and gotten it over with because what they said to me sticks to me to this day and it affected me, (turned) me into the person I am today. I was bullied and they called me fat and they called me horrible things," she added.