"I've made the very difficult decision not to return for another season," Spears, who mentored the show's youngest contestants, said in a statement on Friday.
Her rep confirms that Fox, which airs the singing competition, has been informed of her decision.
A source told PEOPLE Thursday that the pop superstar intends to focus on her music now that she's done with the hit show.
"I had an incredible time doing the show and I love the other judges and I am so proud of my teens but it's time for me to get back in the studio," Spears said Friday.
And she hints that she may also be back on tour in 2013.
"Watching [the contestants] all do their thing up on that stage every week made me miss performing so much!" she said. "I can't wait to get back out there and do what I love most."
TMZ reports that Spears is "in talks" to do a longterm Las Vegas show.
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