Born with Marfan syndrome and lipodystrophy – an extremely rare condition that means she cannot put on weight – she weighs just 27kg. She is blind in one eye and has limited vision in the other.

“I would, of course, instantly in my mind feel angry or upset or confused and thought ‘why are they doing this?’” says the 27-year-old whose journey from cyber-bullying victim to anti-bullying activist has been chronicled in an award-winning documentary Brave Heart: the Lizzie Velasquez Story, which is released in Australia today.

“…they always encouraged me to pray for [the bullies] in whatever they were going through.”

Raised by Catholic parents, Lizzie learned from them that “hurt people … hurt people.”

“Whenever that started happening my parents quickly stopped and reminded me that I couldn’t be mad at what those people were doing because I don’t really know what’s going on in their lives. They might be going through something really tough and the only way they can express themselves is through hurting someone else.

“And even though I was on the other side of it, instead of getting angry, they always encouraged me to pray for them in whatever they were going through.”

Thanks to her parents, who treated her just like any other child, Lizzie had no idea that she looked any different from anyone else until she started school and the staring and nasty comments started.

But whenever she was bullied, she managed to follow her mother’s advice to keep her head up and smile.

That all changed when she was 17 and she came across an eight-second YouTube clip that attracted four million hits and a torrent of cruel comments. It was a clip of an interview she had given on a chat show as a child. She was called “a monster” and “the world’s ugliest woman” and one person even advised her to put a gun to her head. Other hurtful comments were “Kill it with fire!” and “Why didn’t her parents just abort her?”

“I was blaming God for a long time because I thought he’s the reason why I’m having to deal with all of these horrible things.”

Scrolling through the thousands of comments, Lizzie was devastated to find that not even one was supportive.

She cried her eyes out and, disgusted by her appearance, she began to pray every night for God to change the way she looked. Now she sees it as a hidden blessing that God didn’t answer that prayer. But at the time, she was angry.

“When I was struggling and times were really hard, I didn’t know who to blame and I was blaming God for a long time because I thought he’s the reason why I’m having to deal with all of these horrible things.

“But fast forward a few years and now I see everything in my life, even the hard things, as a huge blessing.”

Adopting her mother’s fighting spirit, Lizzie decided not to let her syndrome define her but to use the negativity of her bullies to “light my fire to keep going” and work hard to achieve her goals. She decided then and there to become a motivational speaker.

A key turning point in Lizzie’s journey from cyber bullying victim to global anti-bullying activist came in December 2013 when she gave a TedX talk titled “How do you define yourself?”, which has garnered more than 13 million views on the internet. In it she challenged her audience not to let other people define their goals, success and accomplishments.

She has her own YouTube channel and is writing her fourth book.

Now aged 27, Lizzie Velasquez is beautiful but not in the ordinary way. Her eyes, her hair and her smile all glow, reflecting an inner beauty forged by the courage and strength to forgive the haters and the bullies.

“I think my faith journey has been a very interesting one,” says Lizzie, who says her Catholic faith helped her through the hard times.

“It’s grown with me from the time I was really young until now when I think I’m still on my faith journey.”

Now a host of celebrities such as Kristen Bell and Chris Hemsworth have featured on a video called “I’m With Lizzie” in in support of her anti-bullying stance.

“It feels very surreal. I started doing work back when I was around 18 years old and I really was excited when I was able to tell my story to five or six regular people and now to have people around the world know who I am and even have celebrities know who I am is very amazing,” she says.

“I thought that I would only believe I was beautiful if other people believed I was beautiful. That’s totally not true at all.”

By concentrating on the positives such as her gorgeous hair, Lizzie has come to accept her appearance, but she says it is a process of transformation.

“I thought that I would only believe I was beautiful if other people believed I was beautiful. That’s totally not true at all. I know I’m beautiful because I truly believe it from the inside out,” she says.

“It was a process over a few years. I don’t think it was ever a light switch moment where I thought OK today I feel like I completely accept myself and everything is wonderful, so it was taking it day by day and actively telling myself and reminding myself that I am brave and I am courageous and I am all of these other things and if I can be the person to remind myself of that I can keep doing it until I believe it, and that’s how my brain has been working over the past few years.”

As for the documentary, which has won honours at every film festival it has appeared in, Lizzie says she was changed by the experience.

“The journey and the lessons that I learned throughout the whole process of being vulnerable and being OK with sharing my weaker side on camera really, really helped,” she says.

While she has to carefully manage her condition, she loves all the travelling to speaking engagements.

“I really enjoy it. It’s hard for me to say what I do is work because I really live out my dream job and to be able to travel and meet new people and hear other stories and how they have overcome so many different things, I adore it, I really do.”