Katie, who is expecting her fourth child, made the admission this morning (19 June) during an appearance on ITV1's Daybreak, adding that it will also be "unbelievable".
Speaking to hosts Lorraine Kelly and Aled Jones, Katie said: "Lots has happened - the last book finished off when I'd just married Alex.
"Trust me, there's loads in this book. It's unbelievable. It's quite disturbing, it's quite an emotional book.
"Obviously I had to go through a lot of things emotionally - a lot of things I had to put up with. Yeah, it will be an interesting read."
Former glamour model Katie is set to release her autobiography, called Lipsticks, Love and Lawsuits, in October and it will focus on the last three years of her life.
It will also feature her account of her relationship with Argentinean model Leandro Penna and she will apparently give her side of her bitter feud with Peter and his manager - who she was once represented by too.
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