Announcing the news in an interview with The Sun last week, Katie revealed that she had found intimate emails between Kieran and their children's nanny Nikki Brown.
Nikki went on to deny these allegations, and insisted she had not slept with Kieran, however, he has now admitted to the affair.
Speaking to The Sun once more, he revealed he slept with Nikki multiple times, insisting it was 'meaningless' and a result of his sex addiction.
He explained: "This wasn't a big love affair, I didn't fancy Nikki. I'm a sex addict and needed a thrill.
If our nanny had been 80 I'd probably have tried to manipulate her into having sex too."
He also revealed he was coming clean about the affair as he couldn’t stand to have Katie branded a liar.
"I've hurt her, betrayed her and now need to stand up for her. However bad I feel, I know I have made Katie feel worse."
Nikki branded her former employer a liar after Katie confronted her about emails she'd found between her and Kieran.
She scathingly added: "Katie wanted a divorce, she wants an excuse to get out and blame someone else."
But Katie took to Loose Women to confirm Kieran had, in fact, been having a year-long affair.
WATCH: Katie confirms Kieran had been sleeping with their nanny
So, we guess the cat's out the bag now, eh Kieran?
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