BRIDE-to-be Britney Spears has designed a $270,000 playground in her back garden to keep her fiancé’s kids happy. The singer, 22, ordered a pool with slides, giant playhouse, swings, roundabout and activity centre. Britney will become a stepmom to Kevin Federline’s two-year-old daughter Kori and newborn son Kaleb if their wedding goes as planned. A builder at her house in Malibu, California, said: “She wants no money spared on the garden. She takes her role as stepmother seriously and can’t wait to watch them having fun.” Shar Jackson, 25, who Kevin, 26, dumped for Britney said: “She seems nice and Kori likes her. I don’t bear her ill will.” Britney is said to be marrying in Santa Barbara in November.