Britney Spears Walks Off X-Factor Set--Again! Do you think she is worth being a judge?

They might have to hold this one against her.

X-Factor judge Britney Spears walked off
the show's set during auditions Friday afternoon--just one day after TMZ
reported she stormed off "angrily" following a hopeful contestant's
cover of one of her hits. (The singer, 30, slammed
the report via Twitter later that day. "Britney walks off??? LOL was
just taking a little break people," she wrote. "I am having the BEST
time!!!")

PHOTOS: Britney's wild past

"After a very popular contestant finished, Brit stood up and
immediately walked towards the tunnel where judges enter," a show source
tells Us Weekly
of the pop star's dramatic exit Friday afternoon--adding that it wasn't
clear what spurred the departure. "Her bodyguards [and entourage]
jumped up and ran after her. She was moving fast . . . It was odd." (The
witness adds that, after a little while, "she came back," as though
nothing unusual had happened.)

PHOTOS: Her best and worst looks

During Thursday's auditions, the X-Factor source told Us Spears--who will reportedly see a $15 million payday for her stint on the show--seemed "uptight" compared to her fellow judges Simon Cowell, LA Reid and Demi Lovato. "Her body language was reserved," the source shared.

"Demi, Simon and LA," on the other hand, "seemed very relaxed and
engaged with contestants and the audience," the witness recounted.