Speaking on the show, which airs on Monday, Cher revealed all about how both she and her family have been targeted with sick online jibes and threats.
"The worst thing I've suffered was when I received a death threat against my mum," she said.
"It was her birthday and she was destroyed. She was a total wreck. I was so angry — say what you want about me, but don't upset her."
The 18-year-old added: "I think these people need help. To do that to someone, there's got to be something wrong with you.
"It sounds strange but I feel sorry for them.
"Maybe they've got a troublesome life, to feel the need to pick into other people's."
And Cher, who finished fourth on the show in 2010, revealed how she was getting hate just minutes after her audition aired.
"People might think, 'Oh, just get over it — they're only talking about your face or your eyebrows or your teeth'," she said. "But they picked up on everything I was insecure about.
"People started picking on me and hammering into me. They were saying, 'You're not pretty,' 'You're really ugly'' 'Why are you doing it?'.
"That's when it started to really to hurt. Right from the very start. "