Britney Spears reveals she turned down role in Chicago because she feared her obsessive method acting would make her 'become a KILLER' - as she admits struggle to shrug off Crossroads role drove Justin Timberlake insane
The Toxic hitmaker, 41, revealed in her tell-all memoir that she became so engrossed with the role that she 'didn't know what was real anymore' - which left Justin asking: 'Who are you?'