Royal officials have confirmed that Prince William and the Duchess of Cambridge are expecting their second child, and that the duchess is being treated again for a severe form of morning sickness.
Clarence House, the office for the royal couple, announced the news on Twitter and in a statement on Monday.
"The Queen and members of both families are delighted with the news," the statement said.
The duchess, the former Kate Middleton, is not yet past the 12-week stage of her pregnancy, according to Britain's Press Association.
Clarence House also confirmed that, as with her first pregnancy, the duchess is suffering from a severe form of morning sickness called hyperemesis gravidarum and is being treated by doctors at Kensington Palace.
As a result, the duchess did not attend a scheduled event at Oxford University Monday, leaving her husband to attend alone.
The prince told reporters that the couple were "thrilled" to be expecting a second child.
"It's great news," he said. "But I'm hoping things settle down and she feels better."
Royal officials said it's not clear if she will be able to carry out other planned engagements, each of which will be assessed on a "case-by-case basis."
It is not yet known if the duchess will still make a scheduled solo trip to Malta later this month.
The duchess was briefly hospitalized for the same condition during her first pregnancy, but recovered and delivered without any further complications.
Ontario-based gynecologist Dr. Mathias Gysler told CTV News Channel that although symptoms of hyperemesis gravidarum usually abate after the first trimester of pregnancy, he has seen cases that carry on throughout the woman's entire pregnancy.
Congratulations pour in
U.K. Prime Minister David Cameron, Labour Leader Ed Miliband and the Archbishop of Canterbury were among the first to offer congratulations to the couple on Twitter.
Prime Minister Stephen Harper also tweeted out best wishes for the pair.
Many congratulations to the Duke and Duchess of Cambridge. I'm delighted by the happy news that they're expecting another baby.
— David Cameron (@David_Cameron) September 8, 2014
Fantastic to hear that Prince George will soon be a big brother! Congratulations to the Duke and Duchess of Cambridge on their happy news.
— Ed Miliband (@Ed_Miliband) September 8, 2014
Wonderful news that the Duke & Duchess of Cambridge are expecting second child. Praying for the family, and that morning sickness subsides.
— Justin Welby (@JustinWelby) September 8, 2014
On behalf of all Cdns, @LaureenHarper & I congratulate the Duke & Duchess of Cambridge on this very exciting announcement. @BritishMonarchy
— Stephen Harper (@pmharper) September 8, 2014
The announcement comes just a few weeks after the couple's first child, Prince George, celebrated his first birthday on July 22. Their second child will be fourth in line to the throne, pushing Prince Harry to fifth in the succession ranking.
With files from The Associated Press
