Prince Harry has welcomed the news of the Duchess of Cambridge's pregnancy as "very exciting" - joking that he cannot wait to see his brother "suffer more".
He said Kate was coping with her illness and expressed his wish that the couple would be able to enjoy some privacy during her pregnancy.
The Duke of Cambridge says his wife is "feeling OK" after being treated for hyperemesis gravidarum after falling pregnant with her second child - adding that he was going home to "look after her".
Speaking at Oxford University today, he said: "It's been a tricky few days - week or so - but obviously we're basically thrilled, it's great news, and early days.
"We're hoping things settle down and she feels a bit better."
"It's important that we all focus on the big international and domestic news that is going on at the moment," the Duke said.
The Duke of Cambridge today said he was "thrilled" after it was announced the Duchess of Cambridge is expecting their second child, adding it had been "a difficult few days".
The Duchess of Cambridge, who it was announced today is expecting her second child, may be over the worst of her acute morning sickness in a "few weeks time", the Duke of Cambridge said today.
Royal historian Dr Kate Williams has said that it must be "very hard for William and Kate" after they were forced to announce the Duchess' pregnancy early, meaning "they don't have that early period of privacy".
As with her last pregnancy the Duchess of Cambridge has suffered from hyperemesis gravidarum (severe morning sickness).
This has meant she has been prevented from carrying on her royal duties, forcing the palace to confirm both pregnancies earlier than most parents might go public.
Expectant parents usually wait until after the first trimester.
Royal historian Kate Williams has said that being the 'spare heir' in the royal family can be a difficult position.
Dr Williams described Princess Margaret as: "the example of someone who didn't enjoy being number two."
The Duke of Cambridge arrived alone to formally open The Dickson Poon University of Oxford China Centre Building.
He had been due to be accompanied by his wife but she was unable to attend due to severe morning sickness.
The Duke of Cambridge accepted a small fluffy toy and a bunch of flowers on his arrival - possibly the first gift for the new royal baby.
After it was announced the Duchess of Cambridge is pregnant with her second child we look back at her last pregnancy spent in the spotlight.Read the full story ›
Punters are already placing bets on the most obscure details of the upcoming royal birth following the Duke and Duchess of Cambridge's announcement.
People can predict the baby's hair colour, birth date and whether Kate and William will welcome triplets into the royal family.
Paddy Power are offering 6/4 that the baby's hair will be brown, ahead of fair (5/2), red (3/1) or black (5/1).
There are currently odds of 33/1 the Duchess will give birth to twins and 250/1 for triplets.
Unsurprisingly, bookmakers have described it as "the biggest novelty betting market of the year".
During their last overseas trip Prince William appeared to 'drop hints' that Prince George could soon have a younger sibling.
When Cynthia Read presented the Duke and Duchess of Cambridge with a lace shawl she had made for the young prince, William told her: "You might have to make another one soon."
The presentation, on behalf of the New Zealand government, occurred during the couple’s sixth day of their royal tour.
The storm these comments made was quickly dispelled as the Duchess was seen shortly after enjoying a glass of wine and a white water boat ride.