Lovato Joins Anti-bullying Campaign

The 17-year-old singer has teamed up with activists at teensagainstbullying.org, and admits she suffered at the hands of mean classmates who once teased her for being a working actress.

Addressing the issue, she says: "Bullying is a very serious thing to me, I've witnessed it first hand - I was bullied myself when I was 12."

Lovato claims things got so bad in the classroom, she eventually began home schooling.

But she credits her eight-year-old sister, Desperate Houswives actress Madison De La Garza, with inspiring her to front the campaign.

Lovato tells the New York Post: "She's getting to that age where she could start becoming insecure. I want to be able to help other girls around her age come into their own with a strong confidence in their skin, their size, who they are and everything about themselves."