The Duchess of Sussex is pregnant and is due to give birth in the next British spring, Kensington Palace has revealed.
The news has been announced as she and Prince Harry begin a tour of Australia.
Kensington Palace said the couple "appreciated all of the support they have received from people around the world since their wedding in May and are delighted to be able to share this happy news with the public".
The baby will be seventh in line to the throne.
The Queen and other senior royals were told about the pregnancy on Friday, when members of the Royal Family gathered in Windsor for Princess Eugenie's wedding.
Meghan attended the wedding with Prince Harry, wearing a long, dark blue coat, which sparked speculation she could be expecting.
That speculation intensified when she was seen clutching two large folders in front of her stomach as she arrived in Sydney for the 16-day trip to Australia, Fiji, Tonga and New Zealand.
It is their first official royal tour since they got married five months ago. Their first engagement is on Tuesday, when crowds of wellwishers are expected to congratulate the couple.
BBC royal correspondent Jonny Dymond, who is in Sydney, said of Friday's wedding: "It was there that the duke and duchess chose to inform the most senior members of the royal family.
"The Queen was told, the Duke of Edinburgh, the Prince of Wales, the Duke and Duchess of Cambridge, the Duchess of Cornwall - they chose that day to spread the happy news around and then recover and relax, get on a plane and then put out the news for the rest of us."
Harry and Meghan had not made a secret of their desire to have a child.
She had said, in a 2016 interview, that becoming a mother was on her "bucket list", while Harry said in their engagement interview: "You know, I think one step at a time, and hopefully we'll start a family in the near future."