Katie, now 27, appeared on the 2010 series of The X Factor and was bombarded with abuse from cyber bullies on Twitter.
She has since been busy researching online trolls and their behaviour and is campaigning for a clamp down and a tougher law against those who commit the crime.
Speaking on ITV1's This Morning about the abuse she received, Katie said: "It was really horrific. I'd never experienced anything like that before.
"I had threats of people coming into the X Factor studios when I was live on stage, saying they had a gun and that they were going to kill me.
"Obviously, going up every Saturday night to perform, I was not only scared to be on TV and singing, I was fearful for my life."
When asked by Holly Willoughby why she continued to read the tweets, Katie added: "Because I'm a human being and I couldn't help but want to look at what people were saying."
Katie told Holly and her co-host Phillip Schofield that she has meetings arranged with the House Of Commons in October.
"I really want to make a difference," she added. "It's one thing to say we want to stop the bullies, but it's also supporting the people who are being bullied."
Watch Katie's first X Factor audition below: