"She took more persuading as he really wasn't her type but after a while they started hooking up for a few months.
"It fizzled out and she thought it was finally time to talk all about it in her book - and she's doesn't have too many complimentary things to say about his moves in the bedroom."
In an exclusive extract from her book Reborn in The Sun last week, Katie wrote: "If I'd needed a shelving unit erected, he'd have been perfect.
"Instead of handling me gently and passionately like most women want, he was like a cordless drill on a multi-speed setting!
"He reminded me of a red Bosch that I have in my garage.
"Bang ... bang ... bang, bang, bang.
"At one point I panicked, thinking, 'S***, if he doesn't stop soon, I'm going to be permanently attached to the bed!'
"Mr X wasn't having sex with me, he was having sex at me."
Katie and Riise, 35, were introduced through mutual friend Mark Smith, who appeared as Rhino on TV show Gladiators in the 1990s.
Katie was newly single at the time having split from on-off boyfriend Leandro Penna.
The footballer persuaded Mark to put him in touch with Katie.
The source said of Riise: "He was so persistent she eventually invited him to her home and he was over in a flash.
"After a few meet-ups, they slept together and that carried on for a few months without many people knowing.
"But after a while Katie suspected he wasn't really that into her after a friend spotted him out and about looking cosy with another woman.
"She was hardly besotted with him so she called it off."
Loose Women star Katie was told that Riise was single but after a while discovered that he was in the middle of divorcing his second wife.
Their affair then fizzled out, and Katie rekindled her romance with Argentinian model Leandro.
But he was furious when he discovered old emails between Katie and the footballer.
Speaking in October 2012, after they had split for the final time, he hinted at uncovering her correspondence with Riise.
He said: "I have emails that involve many people that you cannot even imagine.
"Footballers. Famous footballers. International.
"It's a bomb.
"It's explosive.
"It will show what kind of person she really is."
In 2012, Leandro even tweeted screengrabs of emails he claimed to be between Katie and Riise to his thousands of followers, then quickly deleted them.
Mum-of-five Katie - who is now married to Kieran Hayler, 29 - ran into John one last time when awkwardly they ended up travelling together.
She wrote in her new book how she was infuriated when he cruelly told her on that journey he "didn't like her that much."
She fired off an angry text message to him later that day, writing: "You arrogant t***."
She added: "Not only had he never bought me anything, but I reminded him he had never once satisfied me in all the times we'd slept together.
"And, by the way, did he know I'd shagged one of his mates?"
The source explained: "Katie and John haven't seen each other since then and obviously she's since met Kieran and had two more children and is very happy.
"She hasn't looked back and is glad she broke up with him when she did."
Riise has since got married to his third wife Louise Angelica.
He is best known for being part of the Liverpool team that staged an amazing comeback against AC Milan in the 2005 Champions League final.
Known as "The Miracle of Istanbul", the Reds bounced back from 3-0 down at halftime to level the match at 3-3 and went on to win a penalty shootout.
Riise left Liverpool in 2008 after seven years and played at clubs including AS Roma and Fulham before announcing his retirement last year.
He has since returned to play for Indian side Chennaiyan FC.
-News.com.au
