Cheryl Cole Hair Colour!?

Hii i am wanting to Dye My hair the same colour as Cheryl Cole a Really Dark Purpler Colour i've brought this hair dye and its called ... ' be INDIVIDUAL high colour ' - n8 Plum Radiance and on the top it says Mellor & Russell and i have Dark brown Natural Hair Colour also with a few tints of bronzey brown because of the sun or something but will this colour be similar? if not can someone tell me what colour will be? because i know on the back it shows you colour charts on how your hair will turn out if certain colour but before i brought a hair die i wanted to go dark red and it shown up on the packet as dark red due to my hair colour but then when i put it on it went kind of bright red? and that was mahogany it looked dark red on the packet so idon't know how this will turn out can anyone help if it wont look that colour then can someone tell me what colour CherylCole's hair is? thanks xx