Speaking during an episode of Loose Women, Katie explained that as she'd fallen pregnant at 23, and the standard age for smear test invitations is 25, she'd always assumed that doctors performed them as a routine check during pregnancy.
When the topic came up during a discussion with her fellow panellists, the 38-year-old said, 'Talking of smears I think it is quite important, I never had a smear up until this year.'
'I always presumed that, you know when you get letters through the post, I just always threw them away...'
'I thought from the age of 23, I have been pregnant, and I thought when you're pregnant they automatically do smears and check you. It's only until last year that I realised that isn't true.'
Katie has her first child, Harvey, back in 2002, when she was 24, and has since welcomed four other children: Junior, in 2005, Princess, in 2007, Jett, in 2013, and youngest Bunny, who arrived in August 2014, leaving her with a 13 year span where she thought she'd been covered.
Katie told her hosts Lisa Riley, Kay Adams and Coleen Nolan why she hadn't had a test until this year
Having now had a smear test, Katie advised viewers not to make the same mistake as she had.
'It's not nice, it's not comfortable. But I'd advise anyone out there don't be stupid like me and just think doctors check everything because they don't,' she added.
The NHS Cervical Screening Programme invites every woman in the UK to attend a smear test around the time of their 25th birthday. They are then advised to attend every three years until the age of 50, when the rate is reduced to every five years.
Viewers praised the show for highlighting such an important issue, with one tweeting '@loosewomen Been putting off my smear test for a couple of months, but watch this I've just booked it. #Priorities' and another adding 'Very pleasing to see @loosewomen covering these issues'.