Katie, 36, posted the black and white snap on her You Gossip site last night (17 August) and it shows a little baby fast asleep in a blanket.
Until now, Katie has only teased her followers with a photo of her daughter's tiny hand so her they were quick to wonder if this is her.
Alongside the photo, Katie simply commented: "Sooo cute." One fan replied: "She is adorable congrats to you both xx." Another compared her to Katie's seven-year-old daughter, saying: "Definitely Princess number 2. Adorable, angelic x."
Mum-of-five Katie gave birth to her baby girl, who is yet to be publicly named on 4 August. However, after Reveal contacted Katie's rep for clarification on the picture, it was confirmed that the baby is NOT hers.
Were you fooled?!
This weekend was definitely family-filled for Katie and husband Kieran Hayler, as they were celebrating their son Jett's first birthday together.
During the party, Katie and Kieran were pictured for the first time together since news of his infidelity broke on 7 May.
Although Katie initially declared she would divorce Kieran after discovering he had been sleeping with her best friend Jane, the couple are working at their marriage while he receives therapy for a sex addiction.
During one of her Fubar Radio shows, Katie recently confirmed that she was "sticking" to all her wedding vows.
Celebrities who have welcomed babies in 2014:
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