The star, 30, pulled out all the stops for the Fox's Upfront Presentation at the Beacon Theatre in New York yesterday with two thigh skimming mini-dresses.
But she was clearly feeling a little jittery before meeting the press, biting her nails down until they bleed.
The Toxic singer has long chewed on her nails when feeling anxious and four years ago she even vowed to quit the habit.
She said at the time: 'I have to learn to stop biting my nails! I would like to stop worrying so much, because I worry all the time.'
While the mother-of-two has a troubled history, including a high-profile mental breakdown in 2008, her new boss Simon Cowell isn't concerned.
When asked by TMZ if he was worried about her appearing on live television, he said: 'Not at all.'
Britney was joined at the event by her fiance and former manager Jason Trawick, who was recently approved as her conservator alongside her father.
Conservators have legal authority over a person's general well-being, which includes decisions about food, clothing and medical care.
He will reportedly accompany Britney on set each day.
Britney is thought to have negotiated a $15 million pay packet to be a panellist on the show, but fellow new recruit Demi Lovato is rumoured to be earning just $1 million.
Britney and Demi will replace Paula Abdul and Nicole Scherzinger - who were axed after poor ratings on last year's debut series - sitting alongside show boss Simon and music executive L.A. Reid. Britney Spears New Year's resolution: I won't bite my nails
Read more: http://www.dailymail.co.uk/tvshowbiz/article-2144832/X-Factor-USA-judge-Britney-Spears-fingers-suggest-shes-living-nerves.html#ixzz1v4LKLBwk
