The Duke and Duchess of Cambridge are having a baby, it was announced today.
But Kate, 30, was this afternoon on a drip at King Edward VII Hospital in central London after falling ill with acute morning sickness. She is expected to be kept in for several days after being admitted as a precautionary measure.
Sources said the royal couple are ‘incredibly happy but nervous’ after being rushed into announcing the happy news because of Kate’s illness.
In a statement on their website, the couple said they are ‘delighted with the news’.
MailOnline understands that members of the Royal Family – including the Queen – were only told about the pregnancy this afternoon after the decision was made to take Kate to hospital.
However, the Middletons were already aware their eldest daughter was expecting because she was taken ill while staying at their family home in Berkshire this weekend.
Pregnant: The Duchess of Cambridge visited her ‘adored’ prep school St Andrews last week and even played hockey in high heels despite being pregnant
‘The pregnancy is in its very early stages – the couple only found out very recently that they were expecting. But because she has been admitted to hospital and will have to stay in for a few days, they made the difficult decision to make things public,’ said one.
It is understood that the Duchess began to feel ill at her parents’ home in Bucklebury, Berkshire, where the couple were spending the weekend. She was unable to keep any food or water down.
Concerned William finally took the decision, after consulting his doctor, to get her to hospital this afternoon. Tonight he left his wife’s bedside at about 8.15pm after ensuring she was comfortable.
He drove his wife into London from Berkshire with their personal protection officers, declining the offer of an ambulance in favour of using their own, more low-key car.
It is understood that Kate walked in and was in good spirits despite her ill health. Prince William is currently at his wife’s bedside and will remain there until later this evening.
Sources suggested that the Duchess was hooked up to an intravenous drip to increase her fluid and nutrient levels.
Good sport: In this photo from last Friday the Duchess of Cambridge, plays hockey during her visit to St. Andrew’s School, where she attended school from 1986 till 1995, in Pangbourne
Hyperemesis gravidarum (HG) is a rare condition believed to affect up to two per cent of women in pregnancy and is a severe form of morning sickness.
It tends to be more common in young mothers, women who are in their first pregnancy, and those with multiple pregnancies.
‘If it is not treated properly it can lead to severe side effects and problems for mother and baby,’ Dr Lucy MacKillop, obstetric physician at the Oxford University Hospitals trust.
But Midwife Jules Robertson, of the baby chari’ty Tommy’s said: ‘The condition – although unpleasant – poses no harm to mother and baby as long as it is treated, as your baby will take the nutrients it needs from your body – it’s the mum that suffers more.’
In a statement on the couple’s website, they said: ‘Their Royal Highnesses The Duke and Duchess of Cambridge are very pleased to announce that The Duchess of Cambridge 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.’
The baby will be born third in line to the throne. The Queen, Prince Philip and other members of the royal family are ‘delighted’.
Prime Minister David Cameron said on Twitter: ‘I’m delighted by the news that the Duke and Duchess of Cambridge are expecting a baby. They will make wonderful parents.’
In a later comment to television cameras at 10 Downing Street, Mr Cameron said: ‘It’s absolutely wonderful news, and I’m delighted for them and I’m sure they will make absolutely brilliant parents.
‘I’m sure people round the country will be celebrating with them tonight.’
Mr Cameron confirmed he was informed of the news shortly before the public announcement.
‘I got a little note came into a meeting I was having and I found it quite difficult to keep it to myself,’ he said.
William’s uncle Earl Spencer welcomed the announcement, saying in a statement: ‘It is wonderful news and I am thrilled for them both.’
The baby would have been a first grandchild for William’s late mother and the Earl’s sister, Diana, Princess of Wales.
Dr Rowan Williams, the Archbishop of Canterbury, who married the royal couple in Westminster Abbey in April 2011, said: ‘The whole nation will want to join in celebrating this wonderful news.
‘We wish the Duchess the best of health and happiness in the months ahead.’
Scottish First Minister Alex Salmond offered his congratulations to the couple, who are known as the Earl and Countess of Strathearn when in Scotland.
Mr Salmond said: ‘My warmest congratulations and sincere best wishes to the Earl and Countess of Strathearn on this wonderful news.
‘Everyone in Scotland will join me in wishing the couple the very best as they prepare for the birth of their first child.’
Deputy Prime Minister Nick Clegg said: ‘It’s brilliant, brilliant news. (My wife) Miriam and I are as happy and excited as I can imagine the rest of the country is at the news.’
A spokesman for the University of St Andrews, where Kate and William met, said: ‘We are delighted for the couple and will be writing to them to offer our congratulations. They must be very pleased.’
However there are some concerns for the Duchess’s health as acute morning sickness is a serious condition that affects one in 50 pregnant women.
It is not yet known when the Duchess is due to give birth, but she is believed to have found out last month and had not intended to go public with the news because she is still less than 12 weeks pregnant.
The couple’s official statement continued: ‘The Duchess was admitted this afternoon to King Edward VII Hospital in Central London with Hyperemesis Gravidarum.
‘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.’