William and Kate, who were married in April 2011, confirmed her pregnancy last month when she was treated for extreme morning sickness and dehydration.
"Their royal highnesses, the duke and duchess of Cambridge, are delighted to confirm they are expecting a baby in July," St. James Palace said in a statement. "The duchess' condition continues to improve since her stay in hospital last month."
The BBC quoted an unnamed source as saying the couple will not reveal the gender of the baby until he or she is born.
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