Britney Spears has sparked a bidding war after deciding to do a tell-all interview.The 'Toxic' singer - who in the last few months has shaved her head, gone to rehab, fired her manager and battled with her father while trying to relaunch her pop career - has Allure and Vanity Fair magazines fighting over her. A representative for Allure magazine said: "We would love to have Britney,but nothing is scheduled yet."Which ever publication Britney chooses to reveal all to will have the exclusive around November - in time for the release of her new album. Meanwhile, the 25-year-old singer was stopped by police for allegedly speeding on Friday evening. The mother-of-two was stopped at 8.45pm on Sunset Boulevard but was let off with a warning. Beverly Hills Police Sergeant Mike Foxen said: "She was pulled over for speeding. She was warned about her speed and let go. She was not cited."