It's a girl for British PM Cameron and wife

British PM David Cameron and his wife Samantha on holiday in Cornwall, south-west England, August 22, 2010.

London, England -- British Prime Minister David Cameron and his wife, Samantha, announced Tuesday the birth of their fourth child, a baby girl.

The baby was born weighing

6 lbs., 1 oz., and both the baby and mother are "doing very well," Cameron's office at Downing Street said in a statement.

The child had been expected in September.

The Camerons already have two young children, Arthur and Nancy. Their oldest child, Ivan, was severely disabled and died last year at age 6.

Samantha Cameron was visibly pregnant during the campaign that brought her husband to power in May. She scaled back her hours as creative director at luxury brand Smythson after the election.