Kate, Duchess of Cambridge, the wife of Prince William, gave birth to a baby boy on Monday, the couple’s third child who is fifth in line to the British throne. The baby weighed 3.9 kilograms.
The duchess, 36, was admitted early in the morning to the private Lindo Wing of St. Mary’s Hospital in central London, where George, now 4, and Charlotte, now 2, were also born.
The boy is a sixth great-grandchild for Queen Elizabeth II, who turned 92 on Saturday, and her husband, Prince Philip.
See below for our all our updates from the day...
9:00pm: Duke and Duchess of Cambridge leave hospital with son
Prince William and his wife, Kate, have left hospital with their new baby after showing him off to world's media.
William carried the baby in a car seat and placed him into the back of the vehicle, before the family drove home.
The Cambridges are heading back to Kensington Palace, where their two elder children, George and Charlotte, have already returned after paying a visit to their new sibling at the Lindo Wing.
The baby does not yet have a name, but Kensington Palace said it would be announced in due course.
8:55pm: First look at new royal prince
The Duchess of Cambridge has appeared on the steps of the Lindo Wing, cradling her new son who was born earlier today.
Prince William stood by her side, and the couple waved at the huge crowd of well-wishers and journalists who had gathered outside the hospital waiting for a glimpse of the baby prince.
The baby was well-wrapped while his mother looked in good health in a red dress. The family posed for photographs before heading back into the hospital.
8:20pm: Kate and her new son to leave hospital tonight
The Duchess of Cambridge will leave the hospital in central London this evening, together with her new son, Kensington Palace said.
They will travel home to Kensington Palace. Prince George and Princess Charlotte have already returned to the palace.
The Cambridges expressed their thanks to all the staff at the hospital, and also thanked everyone for their wishes on the birth of their new baby boy, the Palace said.
7:45pm: Prince George and Princess Charlotte arrive to meet new brother
The Duke of Cambridge has returned to the Lindo Wing together with the couple's two elder children, George, 4, and Charlotte, 2.
Charlotte turned to give the crowds of journalists and royal well-wishers a wave as she walked up the steps of the hospital, holding her father's hand. George was still wearing his school uniform.
They went into the hospital where they will meet their new baby brother for the first time.
7:40pm: Labour leader congratulates royal couple
Jeremy Corbyn, the leader of Labour Party, tweeted his congratulations to the Duke and Duchess of Cambridge, saying: "I wish them all the best."
Scottish first minister Nicola Sturgeon also sent her congratulations and best wishes to the couple, adding that she was sure the baby's big brother and sister must be very excited by the news.
7:15pm: Prince William leaves hospital to get George, Charlotte
The Duke of Cambridge has left the Lindo Wing to go and see the couple's two other children, Prince George and Princess Charlotte.
It is thought he will bring them back to the hospital to meet their new sibling and their mother.
Crowds outside the Lindo Wing remain strong, with royal fans keen to catch a glimpse of the new prince. William smiled to the crowd and told them he would be "back in a minute", as he left and drove off in a Land Rover Discovery.
5:50pm: Official notice of prince's birth is placed outside Buckingham Palace
A bulletin announcing the birth of the new royal prince has been placed on an easel in the forecourt of Buckingham Palace. The notice contains details about the birth, including the time he was born.
4:35pm: Prime Minister Theresa May offers "warmest congratulations" to Cambridges
British Prime Minister Theresa May has congratulated the Cambridges on their new baby boy, wishing them "great happiness for the future".
The mayor of London, Sadiq Khan, also offered his congratulations.
As did Boris Johnson, the foreign secretary. "Huge congratulations to Their Royal Highnesses," he declared on Twitter.
4:30pm: Town Crier welcomes new royal on steps of Lindo Wing
A town crier in elaborate costume has declared the news at the hospital’s door, clanging his bell to welcome the new royal.
"God save the Queen," he said, to loud cheers from the assembled crowd. Die-hard royal fans dressed in patriotic Union Jack gear have been camping out on the sidewalk, eagerly awaiting news, while the world's media have also descended to the central London hospital.
4:06pm: Kate has delivered a baby boy!
Kensington Palace says the Duchess of Cambridge has given birth to her third child, a boy weighing 3.9 kilograms.
The palace says the child was born at 11:01am (2:01pm UAE time), a few hours after Kate was admitted to London's St. Mary's Hospital in labour.
Prince William was present for the birth of his son, who is fifth in line to the throne. He is a brother to Prince George, 4, and 2-year-old Princess Charlotte.
"Her Royal Highness and her child are both doing well," the Palace said.
The Palace added that the Queen, the Duke of Edinburgh, Prince Charles, the Duchess of Cornwall, Prince Harry and members of both families have been told the news. All are said to be "delighted" to hear about the new arrival.
3:45pm: Will the baby be called Romeo? Titania? Maybe Puck?
As the "Great Kate Wait" continues, some are passing the time by speculating on what the baby will be called.
While most expect the Cambridges to opt for a traditional royal name, some are getting more creative and suggesting they name him or her after a Shakespeare character, given April 23 is the day the great English playwright was born and died.
"If the royal baby isn't called Puck, I'm going to scream," was one comment on Twitter this afternoon.
Others suggesting calling the new arrival Shakespeare, or potentially William, which would of course also be a nod to the baby's father.
2:50pm: Worldwide media frenzy outside Lindo Wing
While interest in the Cambridges' third child has until now been more muted compared with the previous births, large numbers of photographers and broadcasters are continuing to amass outside the hospital in anticipation of the new royal arrival.
Kensington Palace has just tweeted an aerial picture, showing the world's media gathered outside the Lindo Wing as they await news that the Duchess has delivered her child.
2:15pm: Royal fans wave Union Jacks outside hospital as anticipation mounts
Dedicated royal fans are waving flags and toys outside the Lindo Wing.
"We’ve been camped here outside the hospital for 15 days," John Loughrey, 63, from south London, told Reuters. Mr Loughrey was wearing a Union Jack onesie and hat and holding a baby doll adorned with a crown that said 'feed me mummy' every few seconds.
"We’ve been coming out doing this for 21 years. We were here for George and Charlotte and we'll be there for the royal wedding too," he said, referring to Harry and Meghan Markle.
The baby arrives at a time when the Windsors have particularly been in the limelight.
On Saturday William joined the queen and other senior royals, with the exception of Kate, as the monarch celebrated her 92nd birthday at a televised concert.
The queen also played a prominent role at the Commonwealth Heads of Government meeting in London last week, where it was announced that Charles would succeed her as head of the network of mainly former British colonies.
1:50pm: Royal baby expected to arrive on St. George's Day
If the baby arrives today, it will be born on St. George's Day, England's national day.
The timing added to the excitement for royal fans, with many overjoyed at the patriotic symbolism.
However, the name George is already taken by the baby's big brother, so it is not in the running this time around.
1:15pm: Traditional and modern announcement of baby's birth expected
The royal birth will be announced in both traditional and modern fashion.
A proclamation will be placed on an easel in the grounds of Buckingham Palace for the public to see. At the same time, Kensington Palace will release the news on its Twitter feed, as it did when Prince George and Princess Charlotte were born.
The birth will be celebrated with a 41-gun salute in London's Hyde Park -- the standard 21 rounds with an extra 20 because it is a royal park.
The Tower of London will fire 62 rounds: 21, plus 20 because it is a royal palace, and a further 21 because it is in the historic City of London.
12:50pm: Pippa Middleton, Kate's younger sister, also reportedly pregnant
The news that Kate has gone into labour came one day after media reports emerged that her younger sister, Pippa Middleton, is pregnant with her first child.
The Sun on Sunday said that the baby is due in October, citing an unnamed friend. Ms Middleton, 34, and her financier husband James Matthews, 42, married last year.
The Duchess of Cambridge "could not have been more delighted" when she heard the news of her sister's pregnancy, the newspaper reported.
12:30pm: Albert, Arthur, Alice and Mary are favourites for the royal baby's name
Oddsmakers put Albert and Arthur as odds-on favourite names for a boy and Alice and Mary for a girl.
While the gender of the baby is not yet known, betting ran heavily in favour of the child being a boy. Prince William appeared to drop a hint this month as he enjoyed a night out at the football with Aston Villa fans celebrating a late winning goal from Jack Grealish.
William told fans: "I'm going to insist the baby is called Jack", before pausing to add: "…Or Jackie."
However, if the baby is a boy, it will no longer overtake elder sister Charlotte in the line of succession due to new laws agreed across the 16 Commonwealth realms where Queen Elizabeth II is the head of state, including Canada, Australia and Jamaica.
Under the law, designed to end male primogeniture for William's children, any boys born after October 28, 2011 could not overtake their elder sisters.
12:10pm: Press and royal fanatics gather outside hospital
Television crews and journalists have arrived outside the Lindo Wing of St. Mary's Hospital in London in anticipation of the royal baby's arrival.
They join scores of royal fanatics who have been camped outside the hospital on "royal baby watch" since early April.
The expectation is for a swift delivery, after the couple's daughter, Princess Charlotte, was born just two hours and 34 minutes after the Duchess was admitted to hospital.
With Prince George, Kate gave birth 10-and-a-half hours after arriving at the hospital.
11.45am: Official statement released
Kate, the wife of Prince William, was admitted to hospital on Monday to give birth to the couple's third child and the latest member of Britain's royal family.
The Duchess of Cambridge, as Kate is officially known, was taken in the early stages of labour to the private Lindo Wing of St Mary's Hospital in west London where their other two children, George, 4, and two-year-old Charlotte, were also born.
"The Duchess travelled by car from Kensington Palace to the Lindo Wing at St. Mary’s Hospital with The Duke of Cambridge," Prince William's office said in a statement shortly after 8:20am local time (11:20am UAE).
The baby, whose gender has not been announced, will be Queen Elizabeth II's sixth great-grandchild and fifth in line to the throne, after grandfather Prince Charles, father Prince William and the two older siblings. He or she will be given the title HRH Prince or Princess of Cambridge.
Prince Harry, who plans to marry American actress Meghan Markle on May 19, is now bumped to sixth in line to the throne.
The 36-year-old duchess carried out her last official engagement on March 22 before going on maternity leave.
No exact due date had been given, with officials only saying that the baby was due in April.
As in her previous pregnancies, Kate suffered from hyperemesis gravidarum, a severe form of morning sickness. Officials announced both her previous pregnancies before the traditional 12-week mark because she was too unwell to attend public engagements.
A night at the Lindo Wing costs £7,500 (Dh38,600), including a delivery package and two-room suite, excluding consultants' fees.
Kate is being cared for by consultant obstetrician Guy Thorpe-Beeston, who is the surgeon-gynaecologist to the royal household, and consultant gynaecologist Alan Farthing, the Queen's surgeon-gynaecologist -- part of the trusted team who delivered George and Charlotte.
William and Kate met at St. Andrews University in Scotland. They married at Westminster Abbey in London on April 29, 2011.
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