The baby of Britain's Prince William and his wife Kate is expected in July, the prince's office said on Monday.
The pregnancy of the Duchess of Cambridge, 31, was revealed in December when she was admitted to hospital for three days, suffering from severe morning sickness.
"Their Royal Highnesses The Duke and Duchess of Cambridge are delighted to confirm they are expecting a baby in July," the prince's office said in a statement, which also refutes speculation that Kate could be carrying twins.
"The Duchess's condition continues to improve since her stay in hospital last month," it added.
William, the elder son of heir to the throne, Prince Charles, married the then Kate Middleton in April 2011 and were given the titles Duke and Duchess of Cambridge.