The Duchess of Cambridge has been admitted to St Mary's Hospital, London, in the early stages of labour with her third child and the latest member of Britain's royal family, Kensington Palace has announced.
She was taken in the early stages of labour to the private Lindo Wing of the hospital where their other two children were born.
"The Duchess travelled by car from Kensington Palace to the Lindo Wing at St. Mary's Hospital with The Duke of Cambridge," Prince William's office said in a statement.
The palace said she was in "the early stages of labour".
The gender of the baby has not been announced.
The couple, who married in 2011, has two other children; Prince George, 4, and Princess Charlotte, 2.