WATCH: Britney Spears 'Sad To Let Some X Factor Contestants Go'

Britney Spears has revealed that she found it difficult to turn contestants away at the Boot Camp stage of The X Factor USA.

She joined Demi Lovato, Simon Cowell and LA Reid for the second filmed round of the competition in Miami this week.

Following this round, the four judges will be given their categories, before having to select their finalists for the live shows in October.

In her Viddy video, Britney says: "Well we just completed Boot Camp. It was really sad to let some of the contestants go, but somebody's gotta do it."

We are incredibly excited to see Britney and Demi on The X Factor this year. What categories do you think they'll be given?

Watch Britney's video below.

PHOTOS: Britney impresses at X Factor debut

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