Pregnant Katie, who has since married her third husband Kieran Hayler, also said that splitting with the Argentinian model in 2012 was "the best thing" she has ever done.
Katie made the frank declaration during an appearance on ITV1's Loose Women yesterday (27 June), adding that all the details would be in her forthcoming autobiography.
Last week, the former glamour model also branded her second husband, Alex Reid a "rebound" fling, when talking about the book.
Speaking about Leandro to the Loose Women panel, Katie said: "The thing with me and Leo was all a sham actually. The best thing I did was get rid of him.
"I'm not being horrible, you can ask all my friends. I kept telling him to get out of my house. He didn't work - he'd wait for me to come home. There's nothing worse than someone sat on the sofa waiting for you to come home."
Refering to her book, Lipsticks, Love and Lawsuits, she added: "There's more to it than that. You'll have to read the book."
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