Fox made a huge deal out of snagging Britney Spears as a judge on The X Factor during upfronts. And sure, as a pop star and recovering hot mess, Spears is a perfect choice for that panel. But how much judging does she actually plan on doing?

On Thursday, TMZ reported that Britney had walked off the set following a butchered performance of her own "Hold It Against Me." Another source denied that Spears was upset, claiming, "She was just taking a short break."

Regardless of the reason behind her abrupt departure, Spears' behavior may be just the beginning. According to TMZ's follow-up piece, Britney's contract allows for a lot of leeway.

"X Factor" wanted Britney so desperately, she was able to negotiate terms that are "unheard of" — so say people with direct knowledge of her deal. As one source put it, "Simon is a smart and shrewd businessman who knew Britney could make his show and he was willing to give her just about anything to come on board — and he did."

Does that mean we'll see more walk-offs in the future?

Probably. Or at least more episodes carefully edited around Spears chilling away from the judges' table.

For audiences tuning in to see Britney — whether as a competent judge or as a Paula Abdul-esque disaster — her repeated absence could end up being a problem. We were promised Britney Spears, not Britney Spears whenever she feels up to it.

Next time just offer a job to the far more reliable hologram Britney.

[Image via Michael Carpenter/WENN.com]