Cowell's private life has been the subject of a high-profile book from journalist Tom Bower titled The Intimate Life Of Simon Cowell.
"I'm not Simon's mother – I don't give a toss who he f**ks," she is quoting as telling The Mirror.
"That's none of my business. I think Simon thought he'd have complete control over this book. But how dare he bring me into it now? I don't want to be dragged into his little world of debauchery, thank you very much.
"I get on absolutely fine with Simon – and he will be fine – but I am p*ssed off to be brought into it all again."
Osbourne said that she was approached by Tom Bower to reveal information for the book, but insisted that she turned him down.
She said: "I said 'no'. I didn't want to be a part of it."
Osbourne added that she was aware of Cowell's secret relationship with Dannii Minogue, and that she quit The X Factor because of the singer's controlling attitude.
"Dannii wanted to be the mistress of Simon Cowell – and the mistress of X Factor.
"But I didn't leave the show because Simon and Dannii were f**king, I left because she became unbearable. She started bossing everyone around, even the producers."
Sharon Osbourne also claimed that Simon Cowell was secretly seeing glamour model Jasmine Lennard and personal make-up artist Julia Carta while he was with Mezhgan Hussainy.
"We all knew Simon and Dannii were seeing each other, it wasn't a secret. I don't know why he tried to hide it from everyone though – he'd already split from Terri Seymour.
"But it'll be interesting whether the book mentions he was seeing Mezhgan, Jasmine and Julia at the same time."
Simon Cowell's publicist Max Clifford confirmed yesterday that the X Factor judge was in a relationship with Dannii Minogue.
Dannii Minogue has reportedly stated that she is "distraught" over the book's revelations.
> Simon Cowell: 'Engagement to Mezhgan Hussainy was big mistake'
Photo gallery - Cowell's exes: