Spears' September birth

Britney Spears will give birth to her first child with husband Kevin Federline in September, a month earlier than previously thought.

The singer's 14-year-old sister Jamie-Lynn gushes about the upcoming birth in a posting on Spears' official website - but refuses to reveal the sex of the unborn child, or if the 23-year-old is expecting twins, as has been reported.

Jamie-Lynn has moved to Los Angeles with her mother Lynne, so she can be near Britney and the baby when it arrives.

She says: "I get to spend a lot of time with Britney. We are getting ready for the new baby's arrival in September.

"I can't wait. I have been shopping so much for the baby and it is not even here yet."