London, England (CNN) -- British Prime Minister David Cameron and his wife, Samantha, named their new baby girl Florence Rose Endellion, Cameron's office said Wednesday.
The baby was born Tuesday weighing 6 pounds, 1 ounce, 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.
CNN's Laura Perez Maestro contributed to this report.