LIZZIE VELASQUEZ has known the torment of being mocked by bullies from around the world.

    As a 17-year-old surfing the web, the American came across a video of herself on YouTube that described her as the “world’s ugliest woman.”

    The devastated teenager spent days shutting herself from the world behind a wall of tears, thinking her life was over.

    But now 26, the inspirational woman has hit back at the trolls with an anti-bullying documentary about her life, describing her battle with a rare condition which stops her putting on weight.

    “A Brave Heart: The Lizzie Velasquez Story” premiered at the South by Southwest Film Festival in Austin, Texas, in the U.S., on Saturday.

    The 78-minute film charts Lizzie’s inspiring path from cyber-bullying victim to anti-bullying activist.

    Featuring details of Lizzie’s emotional and physical journey through the years, it follows her progress as she attempts to lobby the U.S. Government for the first federal anti-bullying Bill.

    She was born with Marfan syndrome and lipodystrophy, which is a problem with the way fat is distributed in the body.

    At only 5ft 2ins (1.57 meters) tall, Lizzie only weighs 58 pounds (26.3 kg) — just over four stone.

    “All we had known all my life was that I had a syndrome which meant that I couldn’t gain weight.”

    “At the time, I thought everyone looked like me. I didn’t recognize or tell that they didn’t look like me.”

    First bullied as a child in school for looking different, she was horrified to stumble across a YouTube video labeling her “The World’s Ugliest Woman” as a teenager.

    The video, viewed 4 million times, was accompanied by a cascade of cruel comments about her appearance — and suggestions that she should have been killed at birth.

    “It was afternoon. I decided to go look for music on YouTube — and that’s when I found it,” she said. “I don’t even know why I clicked on it but I did and that’s when I lost it.

    “Calling me a monster or asking why my parents didn’t abort me... how in the world can I forgive the people who told me to kill myself?”

    She fought back by giving a TED Talk in 2013 which she said “changed everything.”

    “This is my purpose. This is what I’m meant to do for the rest of my life.

    “I like to think that I’m not only telling my story, I’m telling everyone’s story.”

    Now, Lizzie’s own YouTube channel boasts more than 300,000 subscribers.

    Speaking in a video posted to her channel ahead of her documentary’s showing today, she said: “I’m so excited, I can’t even tell you.(SD-Agencies)