London(CNN) The countdown is over. Meghan and Harry have welcomed a baby boy.
The news was delivered less than an hour after Buckingham Palace announced that the Duchess of Sussex had gone into labor early on Monday with Prince Harry by her side.
"I'm very excited to announce that Meghan and myself had a baby boy earlier this morning, a very healthy boy," a beaming Prince Harry told members of the media at Windsor Castle.
"Mother and baby are doing incredibly well. It's been the most amazing experience I could ever have possibly imagined."
Here's what we know so far -- and what the world is waiting to find out -- about the newest addition to the royal family.
In October 2018, just five months after their wedding, Harry and Meghan touched down in Australia for their first overseas tour as a married couple.
What was already set to be a hectic visit turned into a royal frenzy when news that the couple were expecting broke as they arrived in Sydney at the start of their 16-day tour of Australia, New Zealand, Fiji and Tonga.
Kensington Palace officials were tight-lipped about the Duchess of Sussex's exact due date, other than to say that the baby was due in the spring of 2019.
But at various royal engagements since the original announcement, Meghan is said to have told members of the public the baby was due to arrive around the end of April or the beginning of May.
When the couple launched a joint Instagram account on April 2, fevered speculation followed that a big announcement was imminent.
But the public had to wait more than a month for the Instagram post on May 6 announcing: "It's a BOY!"
"We are pleased to announce that Their Royal Highnesses The Duke and Duchess of Sussex welcomed their firstborn child in the early morning on May 6th, 2019. Their Royal Highnesses' son weighs 7lbs. 3oz," Sussex Royal wrote.
Prince Harry told the media at Windsor Castle on Monday that his son was "a little bit overdue," giving the couple "a little bit of time to think about" names.
We don't yet know where Baby Sussex made his entrance.
In recent years, the Lindo Wing at London's St. Mary's Hospital has been the de facto maternity ward for royal births.
Catherine, the Duchess of Cambridge, gave birth to her three children -- Prince George, Princess Charlotte and Prince Louis -- at the hospital.
It is also where Harry and his brother, Prince William, were born.
But in recent weeks, speculation mounted that Meghan would chose a home birth. This would be more in keeping with the couple's frequent requests for privacy -- a plea they have made since they began dating three years ago, and repeated in the weeks leading up to the birth of their son.
After the birth, Queen Elizabeth II, senior members of the royal family, Princess Diana's siblings and Meghan's family were informed.
Meghan's doctors would have signed an official notice confirming the newborn's sex, weight and time of birth.
This notice would have been taken under police guard to Buckingham Palace, before being framed and placed on an easel in the palace forecourt, for members of the public to read.
This is up to Meghan and Harry, who have bucked recent convention by choosing to avoid a high-profile public "unveiling" soon after the baby's birth.
Harry hinted to gathered media on Monday that the world would have its first glimpse of his son on Wednesday.
The couple have previously said they "look forward to sharing the exciting news with everyone once they have had an opportunity to celebrate privately as a new family."
It could take anything up to 10 days after the birth for the baby's name to be announced.
Speaking to Reuters on Monday, Harry said they were "still thinking about names."
Until then, speculation is rife. The favorites are Albert, Philip and Arthur.
Tradition plays a huge role when choosing a royal name.
Albert, for example, would be a reference to Queen Victoria's husband, Prince Albert, and also to Queen Elizabeth II's father, King George VI, who was known as Albert until his accession to the throne.
But the couple could opt to skip tradition altogether, as Queen Elizabeth's granddaughter Zara Phillips did when she chose to name her daughters Mia Grace and Lena Elizabeth.
Meghan's American background may also influence the couple's choice of name.
Royal babies are given a lot of names -- Harry's full name, for example, is Henry Charles Albert David. But those titled His or Her Royal Highness don't, traditionally, have a surname.
When William and Harry were at school and during their later military careers, they used "Wales" -- derived from their father's official title as Prince of Wales.
As descendants of Queen Elizabeth II and the Duke of Edinburgh, they could also use Windsor, or Mountbatten-Windsor -- both of which are relatively new inventions, adopted during World War I.
As for Meghan and Harry, their child will likely use Sussex -- their assigned dukedom -- as a surname, just as William and Catherine's children use Cambridge at school.
The baby, who is Queen Elizabeth II's eighth great-grandchild, is seventh in line to the throne. He follows Charles, the Prince of Wales -- who is currently the next in line -- followed by William, his three children and Harry himself.
Meghan and Harry's baby won't automatically become a prince.
That's because in 1917, King George V limited the use of such titles within the royal family, and the couple's child will be too far down the line of succession.
However, the Queen could step in to overrule that decree -- as she did with William and Catherine's younger children, Princess Charlotte and Prince Louis. As third in line to the throne, George was automatically a prince.
Baby Sussex is the first British-American baby born into the royal family.
He will automatically be a British citizen, but his parents will have to report his birth to an American consulate in order for him to obtain US citizenship.
He will be eligible because he was born in wedlock abroad to an American citizen who has lived in the US for a period of five years, at least two of which were after the age of 14 -- according to the US Department of State.
News of the royal baby was a largely symbolic landmark for the UK's history books, particularly at a time when Britain is busy cutting its ties with the European Union, writes Jane Merrick for CNN.
The new prince "will not only have that American heritage, but will also be the first biracial baby in line to the British throne," she said.
"Any new baby is a symbol of hope for the future of any family. But these expectations will be made all the heavier for the newest member of the royal family -- particularly at a time of uncertainty and upheaval in the UK."
According to Merrick, Meghan and Harry's wedding was a "much-needed counterpoint to the climate of fear and hostility over immigration that has become magnified since the Brexit referendum."