Kate Middleton’s pregnant!

A year after tying the knot, the Duke and Duchess of Cambridge are on the threshold of fulfilling the promise of their magnificent wedding. The happy couple have shared the news that they are expecting their first baby, who will become third-in-line to the throne.

William and Kate confirmed that the Duchess is in the very early stages of pregnancy, and they will welcome the new addition to the Windsor royal line sometime in 2013.

The statement issued by Clarence House simply read: “Their Royal Highnesses The Duke and Duchess of Cambridge are very pleased to announce that The Duchess is expecting a baby. The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall and Prince Harry and members of both families are delighted with the news.”

Despite the excitement being generated, the world will have to wait for its first glimpse of the expectant Duchess, who has been admitted to King Edward VII hospital with acute morning sickness and is expected to stay in hospital for several days, requiring a further period of rest once discharged. The future Queen has now cancelled her next three engagements in order to fully recover.

Kate’s condition also means the couple have had to announce their joy earlier than intended. It is understood the pair wanted to keep mum until the brunette had completed her first trimester, however her stay in hospital meant confirmation was brought forward to avoid speculation about the Duchess’ health.

Already one of the most photographed women in the world, Kate’s growing tummy will be the focus of much interest once she is back on her feet again. And her maternity fashion will no doubt be closely followed by fans of her trend-setting style.

Now, the pressure is on for the government to push through new royal succession laws to ensure that William and Kate’s baby becomes heir apparent to the throne. The existing law favours the first-born sons of monarchs. The reform will mean that if the Duke and Duchess’ first child is a little girl, she will take precedence over any younger brothers in the order of succession.

Confirmation of the royal couple’s happy news comes after intense whispers that the Windsors were protecting something special, and in this week’s issue, HELLO! Magazine correctly predicted what the world has been waiting for.

The Duke himself sparked speculation during a recent visit to Cambridge when he accepted a baby romper suit from a well-wisher. Mum Samantha Hill handed the royal a pale-blue baby suit which bore a little helicopter on the front and the message “Daddy’s little co-pilot”. Accepting the gift, William beamed and said: “I’ll keep that.”

With the future King’s impending paternity now confirmed, messages of congratulations have already began to pour in for him and his wife on Twitter, with Prime Minister David Cameron being one of the first to share his best wishes. “I’m delighted by the news that the Duke and Duchess of Cambridge are expecting a baby. They will make wonderful parents.” he tweeted.

Meanwhile, Labour leader Ed Miliband wrote: “Fantastic news for Kate, William and the country. A royal baby is something the whole nation will celebrate.” Given that the palace hasn’t yet confirmed how many weeks along the Duchess is – saying only that Kate was under the 12-week stage – royals watchers will be left guessing as to when exactly the nation will be able to “celebrate”.

A summer baby is the most likely eventuality, and in a happy coincidence the big day could even coincide with Prince William’s own birthday, which falls on June 21.