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While much had been made of Britney Spears' demands before she signed on as a judge for "The X Factor," TMZ is reporting she had one main stipulation: she had to make more than Jennifer Lopez did on her freshman season of "American Idol."

The gossip site reports Brit's "intractable demand" was to score a payday bigger than Lopez' $12 million first-season "Idol" salary. Spears reportedly got her way: she's said to be making $15 million - though TMZ says Brit wanted $20 million.

Lopez was given a substantial raise for her second go-'round on "American Idol," but the site says it's less than the $20 million that has been reported. It's unknown if she'll return as a judge next season, but declining ratings certainly don't help her case. If she's offered less than Britney to come back, the site says Lopez would likely walk.