Youngest kids Jett, six, and Bunny, five, are with their dad Kieran Hayler.
Katie is isolating at home with her eldest son Harvey, 17, whose health conditions make him vulnerable to coronavirus.
The former glamour model revealed she hasn't seen the rest of her brood for a month.
Opening up to New! about how tough she's finding being away from her youngest children, Katie said FaceTime is getting her through.
Katie said: "Harvey is one of those who are at a high risk of dying if they get it, so I haven’t been able to see my other kids. It’s hard, but I’ve got FaceTime. In that respect I’m struggling – it’s been a month since I’ve seen them. But I can’t risk it for Harvey."
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With everything going on in this crazy world right now, I just wanted to come on today to wish everybody a Happy Mother’s Day. These are very strange times and I am so thankful to be spending the day with all 5 of my wonderful children. I know many people (including myself) weren’t able to see their mums today and my thoughts are with you all. Please stay safe everyone, follow the government’s advice, #stayhome and lets #Bekind to each other. Katie x
She also hasn’t seen her beloved mum Amy for a fortnight. She is suffering from a chronic lung condition.
Katie said: "Believe it or not, I don’t mind my own company. But my mum is dying and the last time I saw her was two weeks ago. I couldn’t even go in the house. I was in the garden and she was in the conservatory."
The model added that if she didn't have Harvey to care for, she would become a government volunteer.
Harvey is one of those who are at a high risk of dying if they get it, so I haven’t been able to see my other kids.
Showing her appreciation for the NHS, she said: "It’s so hard, but that’s why you’ve got to give it to the NHS and the carers out there who are helping everyone."
Katie previously revealed she was struggling to home school her eldest during the UK lockdown.
She said: "It isn't easy on my own, but we're making it work."
Katie will next be on screen in Channel 4's Celebrity SAS: Who Dares Wins.
She'll appear on the show alongside Joey Essex, Anthea Turner and former Strictly Come Dancing professional dancer Brendan Cole.
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