It's been nearly two years since Demi Lovato sought treatment in rehab for, among other things, an eating disorder.
And during her appearance on Monday's Katie, the X Factor judge offers up a startling revelation as to when she began having body image issues.
"I remember being 3 years old in a diaper and rubbing my hand over my stomach," Lovato recalls to host Katie Couric. "I remember thinking in my head, 'I wonder if one day this will ever be flat?'"
Lovato goes on to open up about the bullying that she endured at the age of 12, with other girls teasing the starlet about her weight.
"It played more of a toll on me than if I was physically abused in school," the now 20-year-old Lovato says. "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."
She is now using her past experience with bullying to help others.
Lovato announced on Thursday that she is the new ambassador for Secret deodorant's "Mean Stinks" antibullying campaign.