It was a rivalry that generated almost as many headlines as the competition itself.
And now the 'feud' between Sharon Osbourne and Dannii Minogue is back in the news again.
Following the release of extracts from Dannii's soon-to-be released autobiograpy, Sharon's daughter Kelly has leapt to her mother's defence with a number of comments on her Twitter page.
In the book – Dannii: My Story – the Aussie beauty claims that Sharon reduced her to tears on her first day at the X Factor.
The mum-of-one said that Sharon "bowled in" and "demanded to know why I hadn’t gone to the press to tell them what a nice person she was", adding: "The minute she left I burst into tears."
And now Kelly, 25, has had her say.
"I'll be the first one to admit that my mother did not play her cards right when it came to Dannii but trust me when I say Dannii is the devil," she wrote on her Twitter account.
"Dannii, you are so lucky that I respect Simon enough to not tell the truth about what really happened."
Photos: © Rex