'A Brave Heart: The Lizzie Velasquez Story' premiers at the South by Southwest Film Festival in Austin, Texas, today.

The torment of being an object of mockery by bullies from around the world is not new to Lizzie Velasquez 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' premiers at the South by Southwest Film Festival in Austin, Texas, today. The 78-minute film charts Lizzie's inspiring path from cyber-bullying victim to anti-bullying activist.

'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 recognise or tell that they didn't look like me.' 

'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?' 

'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, which 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.

'I finally was able to sleep and I'm feeling rested and ready to go.' 

Director Sara Hirsh Bordo said: 'Bullying is a subject that historically yields heartbreaking stories of hopelessness and in many times, loss. 

'Rarely is there a story of survival and inspiration that continues to crossover ages, genders, and ethnicities… enter the brave story of Lizzie Velasquez.'

The pair met when Ms Bordo asked her to give the TED Talk, which attracted more than 10million viewers. 

'She was a local hero whose time, we found out shortly after, had arrived,' she added. 

'We live in a culture of tremendous meanness. And few people have experienced it more than Lizzie.

'Lizzie chose to not give up, but to forgive and to thrive; as an author, as a speaker, and now as an activist.'

She added: 'What I wanted to show is that this is Lizzie’s film, but it is everyone’s story.'