The reality star and former glamour girl posed with Jett – who was born eight weeks prematurely in August - alongside her husband, and now proud dad, Kieran Hayler for OK! Magazine.
In the photos Jett is cuddled up in his mum's arms wearing a white romper suit, with Katie and Kieran looking proud as punch with their new addition.
Speaking to the magazine, Katie said Jett was doing very well despite his early arrival, and has doubled his size in 12 weeks.
"Everyone who's met him comments on how he doesn't look like a baby who was eight weeks premature because he's so big!" said Katie. "He's healthy. I was massive with my pregnancy - the biggest I've been out of all four pregnancies."
Katie - who is also mum to Harvey, 11, her son with Dwight Yorke, and Junior, eight, and Princess, six, her children with Peter Andre – also said her older children were getting on well with Jett, much to the couple's relief:
"I always said Princess might be a bit funny, but they're both actually really hand-on. Princess tries to copy me, and when he cries she wants to pick him up and jiggle him about.
"'I've always said that I want loads of children. I don't want to grow old lonely! But Kieran has said he only wants one more, and I'm saying 'I don't think so!'. For me, I'll carry on going, but with caesareans, you can only have so many, so I'll carry on and then I joke that I'll then get a surrogate."
New mum Katie also hit back at claims that Kieran should have a paternity test to prove he is Jett's dad because he was conceived so soon after the pair met and got married:
''I'm insulted that people could suggest Kieran should do that - we both are. It's ridiculous and not nice for Jett when he grows up. He's definitely the father, you don't even need to justify it.''
The full feature appears in this week's OK! magazine - out now.