Thankfully, she managed to avoid giving the cameras a proper eyeful, but she was spotted struggling with the top as she sashayed past a line of paps.
Eek! We've all been there!
Desperate not to expose her chest, the braless mum-of-five continued to yank at the skin-tight body's barely there straps and low-cut sides in a bid to keep her boobs under wraps, as she waved at passersby.
Never one to blend into the crowd, like ever, Katie teamed her rather risqué top with a pair of spray on white jeans that boasted a whole lotta distressed detail on the shins.
She ditched the heels and sauntered into the studio in a pair of white trainers. Channeling her inner Sporty Spice, she tied a pearl-adorned sweater around her waist and rocked the coolest pair of tinted sunnies - love!
This is just one of a string of outfits Katie has drawn gasps in lately, though!
On Wednesday afternoon (21 September) she donned a gold spandex catsuit and hatched out of a giant egg to promote her new book, REBORN.
The pictures have to be seen to be believed, people.
She also made waves in head-to-toe burgundy outside the ITV Studios on Monday (19 September).
But back to that itsy bitsy top!
Katie - who showed off her in-credible hourglass shape in the tight number - isn't the only celeb to come close to exposing her nips this week, as Made In Chelsea's Tiffany Watson served up major side boob (and gave us a glimpse of her tit tape - eek!) at the Remembering Elephants event in London on Tuesday night (20 September).
Ah well. If you've got it, flaunt it, right?
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