The singer, who is being mentored by Louis Walsh alongside Brucknell in the over 25s category, was quick to dismiss claims that the controversial hopeful is being bullied in the X Factor house.
Earlier in the week, reports had suggested that Brucknell was considering leaving the competition due to tension with other contestants.
"Everyone has their own opinion of Kitty - she drives me up the wall," Brookes told The Sun.
"I can say for sure she's definitely not getting bullied in the house. There's no bullying going on. She's a tough cookie."
An X Factor source added that the rest of the Over 25s "just can't bear" Brucknell, resulting in her isolating herself from the others.
Speaking of her time on the show, Brookes also revealed that she would like to lose two stone and plans to start swimming to keep fit.
Eliminated Over 25 Jonjo Kerr previously told Digital Spy that the X Factor contestants are is "f**king sick of" Brucknell due to her "crying and moaning about everything".
Watch Kitty Brucknell singing 'Who Wants To Live Forever' below: