The singer, who has performed her Britney Spears and Lady GaGa tribute acts worldwide, received praise from all four judges when she auditioned last week. Since then Brucknell's time as a honeytrap girl, rivalry with fellow Spears impersonator Lorna Bliss and alleged use of illegal diet drugs have been revealed by various tabloids.
According to The Sun, the 26-year-old has been targeted on social networking websites, with users branding her "more annoying than gonorrhoea".
"I have had death threats on the internet," Brucknell told the paper. "People don't like confidence. I hope people write better things about me."
One 41-year-old man from Doncaster is said to have explained in detail how he wanted to see the singer dead. The hate pages have called on like minded users to "spread the word" to help recruit "more Kitty haters".
Her security has reportedly been increased, while an X Factor spokesperson said: "The welfare and safety of contestants is of paramount importance."
However, Brucknell has claimed that the backlash she has faced will prevent her from triumphing in the ITV1 competition: "That's not going to happen," she said.
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Watch Kitty Brucknell's X Factor audition below: