Despite continuously blasting the X Factor and her former mentor Cheryl Fernandez-Versini after her exit in 2010, Katie returned to the show during last night's grand final to join the likes of Chico, Stevi Ritchie and Wagner on stage.
And, as if her performance wasn't enough to get people talking, Katie then hinted she could be returning as a judge next series...
Since leaving the show four years ago, Katie has openly slated The X Factor, stating she wished she had never auditioned in the first place while encouraging new contestants not to enter.
But, last night, the controversial 28-year-old returned to the show and, following her performance, Katie even suggested she could be joining Simon Cowell and her former mentor Cheryl on the judging panel.
She tweeted: "Bye Bye London!! See y'all on the other side.... #seeyounextyear #confirmed #chair."
katie waissel (@katiewaissel24) December 13, 2014
Could she be referring to a judge's seat?
Somehow we can't see Chezza letting that one happen!
Katie's cryptic tweet comes after she made a shock appearance during last night's X Factor final - won by Ben Haenow.
Joining other 'novelty' acts such as this year's Stevi and Chloe-Jasmine Whichello, Wagner and Diva Fever, Katie and the gang performed Black Eyed Pea's track 'The Time (Dirty Bit)'.
And, following her performance, eagle-eyed viewers spotted Katie mouthing "you owe me" to Simon - with the music mogul simply shaking his head back at the star.
But, despite her comment to Simon, it seems Katie didn't really mind taking to the X Factor stage once more.
Shortly after, the singer posted the following Instagram message to her account: "I never really had a chance to say my farewells to London, so I want to thank the show for flying me over and giving me that opportunity.
"Also, to appear on this show 4 years later in whatever context this might be, is a sure fire way to put closure on the past and inspire people to always get back on the horse..."
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Watch Katie's 2010 X Factor audition here: