The former X Factor contestant wore the perfect summer to autumn outfit as she attended the Trader Vic's relaunch party at the London Hilton Park Lane on Thursday night (3 October).
Katie teamed her floral shirt – which showed off plenty of back – with a pair of leather trousers and black ankle boots.
Earlier this week, the singer gave fans a glimpse at her newest tattoo – writing across her ribcage. Alongside an Instagram picture of the ink, she wrote: "#werkingit even at #bedtime LOVE my new #tattoo #mamaliveshere."
It was just three years ago that we were gearing up to watch Katie at the judges' houses stage of X Factor's seventh series. As we all know, she sailed through to the live shows with mentor Cheryl Cole, and eventually finished in seventh place.
And she's been tuning into the current series, airing weekends on ITV, and already has her favourite: Giles Potter!
She tweeted this weekend: "Oh my god I am officially in love with #giles !!!! Where can I get a #giles poster!!!?! #majorcrush #XFactor #bootcamp."
Giles made the judges' houses stage of the competition, so viewers will watch him trying to impress mentor Louis Walsh in St Tropez this weekend in the hopes of making it to the live shows.
Check out some pictures from judges' houses below: