The 'Toxic' singer makes her judging debut in the new clip, which aired during the MLB All-Star Game last night (July 10).
The promo asks whether Spears has been spending too much time with Simon Cowell, as she shows off her ruthless side to several contestants.
She is seen making comments including "predictable" and "you definitely don't have the X Factor".
Britney Spears will be joined by Demi Lovato and returning judges Cowell and LA Reid for the upcoming second season of the talent show.
Simon Cowell recently commented that he was "fascinated" by the shyness of Britney Spears.
The second season will return with a two-night premiere on Wednesday, September 12 at 8/7c, and on Thursday, September 13 at the same time on Fox.