Britney Spears is reportedly working overtime to get herself into tiptop shape before husband Kevin Federline's album release party at the end of the month. A source close to the family said the popstar has enlisted a team of nannies, trainers and nutritionists to help her whittle away the weight she gained after giving birth to baby Sutton just a year after Sean Preston was born. The source says Britney has hired a nanny for each child and is hitting the gym "for hours at a time. She really wants to make a huge splash at Kevin's release party, and she totally wants to outshine Kevin and announce to the world that she's back."