The battle between Britney Spears and her mother, Lynne, is getting more heated by the minute �" fueled by what sources claim is Brit’s shocking new accusation that her mom slept with her ex-husband Kevin Federline!

“In a fit of rage, Britney accused her mom of sleeping with Kevin!” a friend tells Star. “Britney doesn’t know up from down right now. She’s so confused and angry, she told Lynne that she was so backstabbing, that she was probably sleeping ...