After numerous reports she was not returning, The Female Boss took to Twitter to make the news official.
"Just wanted to let you all know that I won't be part of the X Factor panel this year," she wrote.
"I've had a great time on the show, but this year it's time to do something different. I'd like to thank everyone on The X Factor for two amazing years. Stay tuned as I have a very exciting announcement soon!"
The former N-Dubz singer achieved success in her first series, becoming the winning mentor with her group Little Mix.
However, she fared less well during her second stint as a judge, losing all three of her acts early on in the live rounds of the competition.
It has been widely reported that Sharon Osbourne is set to replace her as a judge, returning to the show after a five year absence.
She was reported to have closed a £1.8m deal to rejoin the panel earlier this month.