Sharon Osbourne

Jennifer Lopez and Steven Tyler can't hog the whole spotlight.

Sharon Osbourne, one of the judges on America's Got Talent, may be leaving the NBC competition series.

Osbourne tweeted an ominous message to her new fellow judge Howard Stern on Tuesday. "My darling @HowardStern, money is not the reason I'm not returning to @nbcagt, it's because..." Osbourne wrote, never tweeting the reason.

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NBC Chairman Bob Greenblatt declined to address Osbourne's tweet at the network's Television Critics Association fall TV previews on Tuesday. "This is coming out of context and we don't even really know what's going on," Greenblatt said.

Earlier Tuesday, Paul Telegdy, NBC president of alternative and late-night programming, only noted that executives were hoping Stern would return for another season. "We'd be delighted if Howard wants to come back," he said.

Would you be sad if Osbourne left?