The professional Britney Spears impersonator is seen clashing with Honey Shazab when the remaining 140 singers in the ITV show are taken to Wembley Arena and challenged to sing as a group.
Tensions rise when both girls express a desire to perform the same line of their assigned track, leading to what Shazab describes as "a clash of opinions".
"I have had a bit of a clash with Kitty because we both wanted to do the same bit," she is seen saying. "it's a shame it had to come to that."
Having been informed of the fall-out, Tulisa Contostavlos notes to fellow judges Gary Barlow, Kelly Rowland and Gary Barlow after their routine: "The looks between Honey and Kitty... if looks could kill, them two would be on the floor."
Brucknell declared this week that she "just want[s] to offend people" on The X Factor.
> 'X Factor' contestant Kitty Brucknell's security 'increased after online death threats'
Watch Kitty Brucknell's first X Factor audition below: