The pregnant mother-of-four stunned fans on Wednesday (7 May) when a tweet appeared on her official account accusing Kieran of having an affair with her friend.
It read: "Sorry to say me and Kieran are divorcing. Him and my friend been having a full blown sexual affair for seven months."
Kieran has yet to respond.
Katie's tweet came just three days after it was revealed that she and Kieran are expecting their second child together, and just a couple of weeks after they looked as loved up as ever while on holiday in Cape Verde.
Several pictures of them kissing and looking happy while at their beach resort were posted to Katie's Twitter account between 12 April and 25 April.
The couple jetted to Cape Verde with Katie's children Princess and Junior and their baby son Jett, marking their first family holiday. An upbeat Katie said at the time: "Loving it here. The weather is so good. Cape Verde all the way."
Among the pictures uploaded to Twitter was one with the caption: "Hubby love time." It shows Katie and Kieran sharing a kiss while in the ocean.
Another picture shows them comparing tans –and showing off their wedding rings. A third sees Kieran leaning in for a kiss as Katie strikes a sultry pose on the beach. Several others showed Katie and Kieran kissing, cuddling and generally looking pretty happy.
Among the family moments pictured on camera was a sweet shot of Katie, Kieran, Junior and Princess sitting in the sand with their backs to the camera.
According to Katie's Twitter feed, the family arrived home in the UK on 25 April. Just twelve days later the divorce announcement came.
Katie and Kieran surprised many when they married in January 2013 in the Bahamas following a whirlwind romance and Christmas proposal.
Their son Jett was born in the French Riviera that summer. Katie announced at the weekend that she is around six months pregnant with their second child.
She's also mum to kids Junior, Princess and Harvey from previous relationships.
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More photos of Katie and Kieran's happy holiday below:
Copyright: Twitter @MissKatiePrice