Britney Spears and Kevin Federline's second son may not be called Sutton Pierce. Since Britney gave birth on September 12 it has been widely reported that the baby's name is Sutton Pierce Federline, giving him the same initials as his big brother Sean Preston. But Britney has refused to confirm the name until his picture appears in People magazine and rumors now suggest he is actually called Jayden James. A source told the New York Daily News newspaper: "Grandma Federline calls the child Jayden."Meanwhile, Britney has already shed her baby weight - just a month after giving birth to her second son. The 'Toxic' singer showed off her new slim figure while enjoying a shopping spree in Los Angeles last week. The 24-year-old pop star looked trim in size 10 jeans, a tight black polo top and a v-neck sweater. One onlooker said: "She's back to her best and looked absolutely stunning."Britney has insisted her weight loss is down to an energetic dancing regime. She told friends: "It's more fun than the gym."Britney is planning a Halloween launch party to promote K-Fed's debut album 'Playing With Fire'. She is also begging her own fans to buy her husband's CD and even offering prizes to people who buy it online.