The Duchess of Cambridge,Kate Middleton has today given birth to her third child - a boy weighing 8lbs 7oz - on St George's Day.
Kensington Palace announced that the baby was born at about 11am, after Kate was taken by car before 6am to the private Lindo wing of St Mary's Hospital in Paddington, London.
The birth appears to have taken place without complications. The baby is fifth in line to the throne, the Queen and the Duke of Edinburgh's sixth great-grandchild and a younger brother for Prince George and Princess Charlotte.
A palace spokesman said: 'Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 11.01am. The baby weighs 8lbs 7oz. The Duke of Cambridge was present for the birth.
'Her Royal Highness and her child are both doing well. The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall, Prince Harry and members of both families have been informed and are delighted with the news.'
Royal watchers had been expecting a swift delivery at the Lindo Wing, with the child sharing a birthday with William Shakespeare and Lady Gabriella Windsor, the daughter of Prince and Princess Michael of Kent.
The baby's title is HRH Prince or Princess of Cambridge. Earlier, excitement was building outside St Mary's Hospital, where some fans had been camped out for 15 days hoping for a glimpse of the royal baby.
The timing of today's announcement that Kate had gone into labour, falling on St George's Day, added to the occasion for waiting royalists outside.
John Loughrey, 63, who is part of a group who have been camped outside the hospital, said: 'We are so pleased. We have been here for 15 days. I'm so pleased it's St George's Day. St George himself would be very pleased if the baby's born today.'
Mr Loughrey, from Streatham, South London, said he plans to celebrate the birth with English flags and a portion of fish and chips.
'It doesn't matter if it's a boy or a girl as long as it's a healthy baby and a healthy mother,' he said. 'It's very good for our country and of course Her Majesty the Queen.'
Another member of his group, 82-year-old Terry Hutt, also welcomed the news.
'It's fantastic to have another newborn baby,' said Mr Hutt, who turns 83 at the end of the month and was hoping to share his birthday with the new royal. 'If they were born on my birthday, I would have got a birthday cake.'
Maria Scott, 46, from Newcastle, added: 'I think it's going to be a boy and I think it's going to be quick.'
The group were talking in front of their make-shift camp, including royal memorabilia and a Union Flag tent.
The Duchess is being cared for by consultant obstetrician Guy Thorpe-Beeston, who is the surgeon-gynaecologist to the household, and consultant gynaecologist Alan Farthing, the Queen's surgeon-gynaecologist - part of the trusted team who delivered George and Charlotte.
Highly-trained midwives were also on hand, while experts were waiting in the wings in case of an emergency
For her previous births, Kate had a 23-strong team of top medics working or on stand-by from Imperial College Healthcare NHS Trust - which runs St Mary's Hospital.
Theatre staff were ready, along with a lab technician, replacement anaesthetists and paediatricians, a back-up for the consultant, and workers from a special baby care unit.
Today, press pens opened outside the hospital as journalists, photographers and camera crews waited for confirmation of the baby's arrival. Royal watchers were expecting a swift delivery.
With George, the duchess gave birth 10-and-a-half hours after being admitted to hospital, but Charlotte was born just two hours and 34 minutes after Kate arrived at the Lindo Wing.
The birth was declared in both conventional and contemporary ways.
An announcement was emailed to the press and a celebratory tweet posted on the Kensington Palace Twitter feed - @KensingtonRoyal.
There is also the traditional custom of placing a framed paper proclamation on an ornate gold stand behind the iron railings of Buckingham Palace.
Just like with her first and second children, Kate had been hoping for a natural birth and did not know whether she was having a boy or a girl.
Bookmakers were also waiting to see whether they have to pay out on the name, delivery date, hair colour and weight of the baby.
Predicted names include Alice, Alexandra, Elizabeth, Mary and Victoria for a girl and Arthur, Albert, Frederick, James and Philip for a boy.
George and Charlotte may visit the hospital to see their mother and baby sibling, just as George did when his younger sister was born three years ago.
But it depends how quickly Kate wants to head home.
While Kate was in labour, George and Charlotte were likely to be cared for by their full-time, live-in nanny, Maria Teresa Turrion Borrallo.
The duchess's pregnancy was announced by Kensington Palace on September 4 last year.
Kate again suffered from extreme pregnancy sickness hyperemesis gravidarum.
She went on maternity leave on March 22, but the duchess - and her large bump - attended an Easter Sunday church service in Windsor with the royals on April 1.
She has joked that William is 'in denial' about having a third child.
Although the Queen has four children, the duke is the first future king to have a third for more than 120 years.
In 1897, George V, then the Duke of York, welcomed a daughter - Princess Mary - the younger sister of Edward VIII and George VI.
Unlike William, George V never expected to be king and only became heir to throne when his older brother, the Duke of Clarence and Avondale, died from flu in 1892.