The Osbourne matriarch took a disliking to the Aussie singer when they starred as judges on The X-Factor.
In her autobiography My Story the mother-of-one said that Osbourne barged into her dressing room and started an argument just before her first live X-Factor show in 2007.
Appearing on Australia's Kyle and Jackie O show, she said, 'I haven't done anything that I know of to make her upset.
'The only thing that I know I did was join the show and I think that seems to have riled her a bit.
'But I don't know what I've actually done for her to have these sorts of attacks on me on various TV shows and stuff, and even after all those attacks I don't come back and say anything nasty about her. I don't say she is a bad person, I don't say anything. It's just like, 'I don't know why you are doing this to me'.'
Addressing accusations by Sharon and daughter Kelly that she made the argument up, the 39-year-old said, 'The things I've described in the book are true, they did happen, there's witnesses there.'