Britney Spears is reportedly building a fun-fair in the garden of her new Malibu mansion for her future step children to play in. The sexy star, who is due to marry fiancé Kevin Federline next month, is planning a mini-theme park in the grounds of her $4 million family home for his two children, Kori, two, and newborn son, Kaleb. A source said: "Britney knows it's extravagant but she knows how much children love a fun -fair. " Britney, who is yet to meet the latest addition to her fiancé's family after his former girlfriend Shar Jackson gave birth last month, has already spent time with Kevin's daughter. Sources revealed that the pop babe spent the afternoon painting the toddler' s nails before sending aides out to Toys'R'Us to stock up on gifts. And last week the sexy star splashed out on more gifts for her future step children, buying trendy 'Von Dutch' outfits for the pair and stocking up on personalised thongs for her fiancé.

The couple's lavish wedding will be Britney's second trip down the aisle this year.