Model Katie was left heartbroken this week when she learned that Kieran had allegedly been having a sexual affair with a close friend, Jane, for seven months.
While Kieran has kept quiet on the accusation, his grandmother Rosita Talbot, 80, has told The Sun that Kieran told his mother about the alleged affair and in turn, his mother told Rosita.
"He's only 27," she said. "He shouldn't have done it. I'm old-fashioned. I was married for 53 years. I see Katie a lot and I like her. She is fantastic."
Rosita added: "I blame my grandson. He is very naughty."
Katie sent a flurry of tweets this week telling fans she was divorcing Kieran over the accusation he had been sleeping with her close friend Jane Pountney.
The shock news came just three days after Katie happily announced that she is pregnant with Kieran's second child. They are already parents to son Jett, nearly one, while Katie also has kids Harvey, Junior and Princess from a previous relationship.
In a statement, she then said: "I appreciate most people will have seen my tweets on the subject of my marriage to Kieran.
"I make no apologies for them though it will be appreciated that, sending them immediately after Kieran confirmed to me what he had been doing for the last 7 months, those tweets were a sign of my heart breaking."
She added: "That he was doing it with a close friend of nearly 20 years is hard to understand."
The day of her divorce news, she was seen at the home owned by Jane and her husband Derrick, where it's claimed she confronted Jane about the alleged affair.
Jane has not spoken publicly but Derrick has suggested the allegations are a "storm in a teacup", telling reporters: "A lot of this drama has been a storm in a teacup and there's a lot of misunderstandings to sort out.
"Now Katie has gone and put the whole thing for everyone to read about on Twitter, which she didn't really need to do, and a drunk kiss has turned into a full-on affair."
Today, it was claimed that Katie has asked Kieran to move out of their West Sussex home and into a log cabin in the garden while she sorts her head out and decides what she wants to do next.
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Katie Price's ex-boyfriends in pictures:
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