The TV star, 36, posted the snap from her bed on Saturday (23 August) where her son Jett, one, can be seen beside her in bed.
In the picture, Katie can be seen wearing a grey bra and pink knickers as she lies down on her unmade bed with her arms up above her head.
And it's hard to believe that the tanned former-glamour model had her fifth baby just three weeks ago, when she gave birth to her baby daughter with husband Kieran Hayler.
It is unclear who took the photo. Alongside the picture posted on YouGossip, Katie wrote: "After past months of stress and lack of confidence after what them scum women did to me it's certainly coming back now I've had baby!"
She also posted a selfie in a cute neon skater dress, with the message: "Loving this dress from @pinktigeruk it's all about getting confident again."
The new mum is picking up the pieces of her life after she caught Kieran cheating with her best friend Jane Poutney.
And Katie did not miss the opportunity to once again remind her followers what she really thinks about her former friend.
Next to a picture of Jane, Katie wrote: "Reminder to the mums at her kids schools jane poutney is a home wrecker wh***, if she did it to me she will you,keep her away from husbands."
Despite the betrayal, Katie is sticking with her husband while he undergoes therapy for sex addiction.
Their second child together, a baby girl, was born on 4 August. They have not revealed her name yet.
Katie gave birth prematurely following a difficult pregnancy, during which she discovered the truth about her husband.
She recently told fans it was her mission to get the best post-baby body she's ever had.
Katie also has kids Junior, Princess and Harvey from previous relationships.
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