X Factor judge Sharon Osbourne has revealed her stomach would be "knotted with anxiety" at the prospect of sitting next to former panellist Dannii Minogue during her previous stint on the ITV talent show.
In Osbourne's new autobiography, being serialised by The Sun, she said the situation between her and the Australian singer - who it later transpired had been having an affair with Cowell - became "unbelievably bad".
Osbourne said of Minogue: "The antics behind the screen had gone up a gear with her sticking her tongue in Simon's ear and giggling like a bloody teenager as Louis Walsh and I stood there like a couple of gooseberries.
"For me it made her so unbearable to work with that I just couldn't take it. It was horrible. My stomach knotted with anxiety about it and as each show loomed I would wake up and think 'Oh God, I have to spend the day sitting alongside her again'.
"During filming it was obvious to me that there was some sort of relationship going on between them. And the more it progressed, the worse it became between her and me. It was unbelievably bad."