- Queen Elizabeth must be the first to know that the baby has been born.
- A town crier announces the birth — as does Kensington Palace's Twitter account.
- Kate Middleton greets photographers on the steps of the hospital just hours after having a baby.
- Royal babies all wear the same christening outfit.
The birth of a new royal baby isn't just an exciting life event for the parents — it's an official celebration for the Commonwealth, as well.
Prince William and Kate Middleton are expecting their third child in April. When the time comes, they'll have to follow certain rules and traditions in accordance with royal protocol to mark the occasion.
Here are eight royal rules that apply when a new baby is born.
Queen Elizabeth will be the first to find out the baby has been born.
Prince William reportedly called the Queen on an encrypted cell phone when Prince George was born to make sure that she would be the first to know, according to the Daily Mail.
A town crier will then make the birth announcement to the public.
The town crier position dates back to medieval times when most people couldn't read or write.
Tony Appleton, who has announced the births of Prince George and Princess Charlotte, is known as the "unofficial" town crier (though he prefers the term "independent") because he has no official connection to the royal family.
The town crier's announcement isn't a royal rule for this reason, but it's a tradition of historical significance that Appleton is passionate about continuing.
The news will be displayed on an easel in front of Buckingham Palace.
In a more updated form of the practice, Kate Middleton and Prince William also took to Kensington Palace's Twitter account to announce the births of their two children. Chances are they'll do the same with the third. However, according to the BBC, the post can only go up on social media after the formal announcement is displayed on the easel.
A 62-gun salute at the Tower of London will mark the royal birth.
Gun salutes are also used to mark occasions like the Queen's birthday, the State Opening of Parliament, and Coronation Day, according to the royal family's official website.
Kate Middleton will greet members of the press hours after giving birth.
Mere hours after giving birth to her two children, Kate Middleton has emerged from the hospital with perfect hair and makeup to pose for a photocall with photographers and journalists who camped out waiting for the news to break.
The Mirror reported that Middleton's personal hairstylist was spotted entering the hospital after she gave birth to Princess Charlotte get her photo-ready.
Middleton is reportedly considering a home birth for her third child so that she can have a little more privacy.
The name won't be announced right away.
When both of their children were born, the Duke and Duchess waited two days before announcing their names.
Prince George's full name is George Alexander Louis, and Princess Charlotte's is Charlotte Elizabeth Diana. Royal expert Victoria Arbiter told INSIDER that royals aim to balance traditional tributes to family members with modern baby naming trends when choosing a name
The baby's christening will be performed a few weeks later by the head of the Church of England.
A royal baby's christening ceremony is a private event with no media allowed. No public access was granted for Prince George's christening, but crowds were allowed to gather on the paddock outside the church for Princess Charlotte's, according to CNN.
The royal baby will wear the same christening outfit as many royal babies before them.
The new royal baby with be the eighth to wear this lace gown modeled after an 1841 design made for Queen Victoria, according to The Daily Mail.
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