Pop superstar Britney Spears and her ex-husband Kevin Federline have kicked off their child custody battle in a Los Angeles court. Attorneys for the Toxic singer and Federline met with a lawyer from the Los Angeles County Counsel at the L.A. Country Superior Court on Monday (27Aug07). Spears and Federline have two sons, Sean Preston, 23 months and 11-month-old Jayden James. A hearing has been set for 4 September (07).