Former glamour model Katie, 41, told her fans on YouTube she has made it clear she has wanted to be part of the show on several occasions - and was furious not to be picked.
She also wondered whether the reason she hadn't made it onto the celebrity reality contest was because Simon, 60, 'fancied her'.
But Katie was quick to make it clear that dig about Simon was just a wind up, adding: "Only joking."
Mum-of-five Katie seethed in her latest vlog: "Why the [bleep] did they not have me on Celebrity X Factor?!
"I so wanted to do that, I put it out there so many times."
I'd have blown them away if I sang, trust me!
She went on to blast those famous faces who did make it to this year’s reformatted Saturday night series - but singled Megan McKenna out for praise.
Katie continued: "I am sorry, I normally love X Factor but I have to say that Megan McKenna has to win the show for sure.
"The singers I saw on there the other week… Jesus Christ, I'd have blown them away if I sang, trust me!
"I didn't think they made a good choice there, I don't think the others are that great."
Katie, who failed to make the grade when contenders to represent the UK at the 2005 Eurovision Song Contest were being whittled down, added: "They should have had me on it, they'd have got more headlines and I can sing."
She joked: "Maybe it's because Simon fancies me, wahey!"
"Only joking," Katie quickly added.
One fan commented on the YouTube vid: "Katie you crack me up, I love watching you."
"Enjoyed this video. Megan McKenna to win! Woop woop," contributed another.
And another supporter remarked: "I love Katie and I love this channel ! Post moreeee!!"
- The X Factor: Celebrity airs on ITV on Saturdays from 8.30pm
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