Talking to the News of the World, the Girls Aloud star revealed that she has now become comfortable with her looks and reinforced the importance of youngsters having positive role models.
She said: "I was so insecure, but you've got to accept who you are.
"I don't work out. And I've never dieted! Can you imagine if I did? I actually have to be very conscious to make sure I eat. If I'm remotely run-down, tired or worried then I can drop weight overnight. I eat loads and have big portions but my mum's side of the family is thin.
"I'm hyperglycemic so I have to eat a lot and often, otherwise my blood sugar levels drop. And I have a lot of allergies - wheat and dairy make my skin break out.
"I know my arms can look skinny. I'd rather have them fuller and more womanly. But I like my legs, though. And my hair! The more redheads the better. It's important for every young girl to have someone she can relate to. Oh my God, I'm all for it."
Speaking of her successful career, the singer added: "I've been very lucky and sometimes it's hard to get my head round everything that's happened. It's too weird. I'm launching my own make-up range in Harrods! How did that happen to the tomboy girl who used to climb trees?"
