Duchess of Cambridge in labour: Palace

The Duchess of Cambridge has been admitted to St Mary's Hospital in London, in the early stages of labour, Kensington Palace says.

The Duke and Duchess of Cambridge's second baby is said to be on the way. (AAP)

Kate, the wife of Britain's Prince William, has been admitted to hospital in the early stages of labour, the BBC reported on Saturday.

The new baby will be fourth-in-line to the throne, behind brother George, father William and grandfather Prince Charles.