Duchess of Cambridge
Britain's Catherine, Duchess of Cambridge, visits the Naomi House children's hospice in Sutton Scotney, southern EnglandReuters

Even as the royal family remains tight-lipped about the due date of Prince William and Kate Middleton's first child, a source close to the couple has reportedly spilled the beans.

Kate Middleton has been given an official due date of 13 July, reported The Mail.

"Some of Kate and William's closest pals were at a barbecue hosted by a family friend of the Royals recently. They were all discussing the fact that Kate's baby is due to be born on July 13. Everyone was very excited," a friend of the couple told The Mail.

However, it will clash the Coronation Festival, a four-day event (July 11-14) to mark 60 years since Queen Elizabeth II was crowned. Prince William and Kate Middleton could miss the celebrations if the due is on 13 July as reported.

Britain's Catherine, Duchess of Cambridge, visits the Naomi House children's hospice in Sutton Scotney, southern England
Britain's Catherine, Duchess of Cambridge, visits the Naomi House children's hospice in Sutton Scotney, southern England

Prince Harry has reportedly revealed that the royal couple is expecting a baby boy, though Kate Middleton hinted that it would be a girl, on several occasions.

"Harry has been telling everyone Will and Kate are having a boy and how thrilled he is at the prospect of having a little nephew," a source told Sunday People. "Apparently Kate has always wanted a boy. The close inner circle all know that it's a boy and they're busily buying gifts with a boy theme. There will be an awful lot if blue in their house."

Britain's Catherine, Duchess of Cambridge, visits the Naomi House children's hospice in Sutton Scotney, southern England
Britain's Catherine, Duchess of Cambridge, visits the Naomi House children's hospice in Sutton Scotney, southern England

The royal couple is said to be busy preparing for the baby's arrival, making sure the baby nursery is good but not extravagant.

"They have a small nursery prepped, but it's humble. Kate felt it wasn't worth the money to go all-out," a source close to the royal couple told US Weekly. "For the precious first weeks, Kate wants the baby to sleep in their room."

"She is keeping it a surprise, even to family. It's beautifully decorated, and there has been some involvement from an artist," the source added.

Britain's Catherine, Duchess of Cambridge, arrives for a visit to the Warner Bros. Studios at Leavesden in southern England
Britain's Catherine, Duchess of Cambridge, arrives for a visit to the Warner Bros. Studios at Leavesden in southern England

Prince William and Kate Middleton are currently staying in Nottingham Cottage and will be there till the apartment 1A in Kensington Palace is ready for them to move into. The baby nursery at the apartment 1A is expected to be more extravagant than the one in Nottingham.

Britain's Catherine, Duchess of Cambridge arrives to visit The Willows Primary School in the Wythenshawe district near Manchester
Britain's Catherine, Duchess of Cambridge arrives to visit The Willows Primary School in the Wythenshawe district near Manchester