Princess Kate expecting first child, in hospital for pregnancy-related condition

The Royal Family is looking forward to welcoming another prince or princess into the world.

Their rep confirmed to Fox News that Princess Kate and Prince William are expecting their first child.

"Their Royal Highnesses The Duke and Duchess of Cambridge are very pleased to announce that The Duchess of Cambridge is expecting a baby," the rep said in a statement. "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."

The rep also confirmed a bit of scary news, saying Princess Kate had been admitted to the hospital.

Related: Is Princess Kate's medical condition a sign of twins?

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"The Duchess was admitted this afternoon to King Edward VII Hospital in Central London with Hyperemesis Gravidarum," the rep said. "As the pregnancy is in its very early stages, Her Royal Highness is expected to stay in hospital for several days and will require a period of rest thereafter."

Hyperemesis Gravidarum is very acute morning sickness, which requires supplementary hydration and nutrients.

The rep would not say how far along she is, only that she has not yet reached the 12-week mark.

The confirmation of her pregnancy was greeted with congratulations.

Prime Minister David Cameron wrote on Twitter that he was "delighted by the news," saying the royals "will make wonderful parents."

As the first-born to William — who is second in line for the throne after his father, Prince Charles — the couple's child stands an excellent chance of one day becoming monarch.

Whether boy or girl, the child will be next in line behind William in the line of succession to the throne, Cabinet Office officials have said.

Monday's news comes weeks after a so-called 'pal' of the Princess, Jessica Hay, blabbed to a magazine that Kate was pregnant.

“They’re planning to make an announcement in December. William and Kate are focused on starting a family,” she tattled.

She also added that the future King and Queen of England were pretty far along in baby planning.

“It seems very traditional, but of course they’ll be happy with boys or two girls, they don’t want more,” she said. “They’ve discussed it endlessly and don’t want to be older parents.”

William and Kate, both 30, were married on April 29, 2011, after dating for eight years, in what was the most-watched wedding in history, with estimates ranging from 500 million to 2 billion people.

This year, Middleton was involved in a photo scandal when topless shots of her sunbathing on a private balcony were published in several newspapers and magazines.

The Associated Press contributed to this report.