St James's Palace and Clarence House have confirmed the month in which Prince William and Kate are expected to become parents.
"Their Royal Highnesses The Duke and Duchess of Cambridge are delighted to confirm they are expecting a baby in July," the statement read.
"The Duchess's condition continues to improve since her stay in hospital last month."
By referring to "a baby", the statement is thought to have scotched rumours that the royal couple may be expecting twins.
The couple announced the pregnancy on December 3 - earlier than the usual 12-week point after Kate was taken to hospital with hyperemesis gravidarum (acute morning sickness).
[The Duchess of Cambridge with Olympian Jessica Ennis]
Kate left London's King Edward VII Hospital three days later and later stayed at Kensington Palace for a period of rest.
She made her first public outing since her stay in hospital at last month's BBC Sports Personality of the Year Awards.
The first official portrait of the Duchess, painted by Paul Emsley, was unveiled last week.
Duchess of Cambridge turns 31 - photo gallery: