Why Did Britney Spears Walk Off ?X Factor? Set?

Britney Spears' first day in her new role as X Factor judge got off to a bumpy start. Spears even walked off the set at one point, leaving four contestants hanging. Why did she walk off?

It all started when Spears made her X Factor debut at the Frank Erwin Center in Austin, Tex., in front of a crowd of 4,000 eager singers.

At first, the 30-year-old judge was happy and cordial. She had nothing but nice things to say about the contestants, even telling one teen boy he could be bigger than Justin Bieber, according to E! News. She tweeted during the auditions. Texas has a lot of talent - seriously! she tweeted. Loving @TheXFactorUSA auditions so far.

Spears sat in former judge Paula Abdul's seat. She and Demi Lovato replaced ousted judges Abdul and Pussycat Dolls singer Nicole Scherzinger.

E! News reported that about 14 soloists and groups performed for the X Factor judges, but after the tenth one, that was when something odd happened. Spears was escorted backstage and did not come back to view the last four contestants. Lovato, Simon Cowell and L.A. Reid were left to judge alone. None of them mentioned her departure, even as the crowd yelled, Where's Britney?

TMZ reported that Spears walked off the set because she was upset after a contestant butchered her song Hold It Against Me during an audition.

Twitter even began trending with the hashtag #Britneywalksoff as news spread of Spears' X Factor snafu.

But the Til The World Ends singer insists that everyone is simply overreacting.

#Britneywalksoff??? LOL was just taking a little break people. I am having the BEST time!!! she tweeted to her 17 million followers on Thursday night.

Spears came back for the second show taping and stayed the entire three-hour shoot, according to E! News, adding that she even loosened up a bit. She chatted more with fellow judge Lovato, dancing during a hip-hop trio's performance and even snipped at Simon when he was especially mean to one contestant.