Britney Spears not all there on The X Factor first day

Britney Spears' first day as an X Factor judge ended in confusion when she walked off the set during auditions.

Four contestants had to try-out without the benefit of looking at Spears or hearing her critique of their performances.

TMZ.com reports the Toxic singer appeared to be far from happy when a contestant butchered her song Hold It Against Me and abruptly left the Austin, Texas audition room on Thursday (24May12), but a show insider insisted the pop superstar just "needed a break".

The day started off well with Spears wowing contestants and members of the audience by cracking jokes and arguing with fellow judge Demi Lovato about the talents of one unnamed performer.

Spears and Lovato were announced as the new judges on The X Factor earlier this month (May12). They replace Nicole Scherzinger and Paula Abdul on the talent show.