Nicole Scherzinger was too afraid to leave her hotel room after she received death threats last year.
The pop star was left shocked when the threatening messages started getting sent to her during her judging stint on the talent show because she did not realise people could be so "hateful".
She said: "It breaks my heart. Last year, I had death threats on 'X Factor' USA. That kind of ruined me. I didn't want to leave my hotel room. I didn't know that people could conjure up such thoughts - so hateful."
Scherzinger is now a member of the judging panel of the UK version of the show and death threats have returned - but this time for her act, ex-model Rylan Clark.
The former Pussycat Dolls star was horrified to read the letters and wishes people could give him a chance before making nasty assumptions.
She explained: "It really frightened and scared me when I got death threats so it upset me to hear Rylan had to go through that pain.
"To read some of the comments he has had hurts me too. People need to give Rylan a chance. Everyone that gets to know him has a great fondness and affinity with him."
The 34-year-old beauty has also promised to stand up for herself when the live shows kick off on Saturday night.
She said: "I am a little tougher this year - to succeed and be resilient in this industry, you must be."