The Duke and Duchess of Sussex told the Royal Family about Meghan's pregnancy at Princess Eugenie and Jack Brooksbank's wedding three days ago, it emerged today.
Harry and Meghan had attended the ceremony and reception along with most other senior members of The Firm at St George's Chapel in Windsor Castle on Friday.
The couple then arrived in Sydney today ahead of a hotly-anticipated 16-day tour which will take in Australia, New Zealand, Fiji and Tonga.
Harry and Meghan were wed at Windsor Castle in May and the news was announced on the eve of their first tour outside the UK and Ireland.
The Queen, the Duke of Edinburgh, the Prince of Wales, the Duchess of Cornwall and Duke and Duchess of Cambridge are said to be "delighted" for the couple.
Doria Ragland, the mother of the duchess, is "very happy about this lovely news" and "looks forward to welcoming her first grandchild".
A Kensington Palace spokesman said: "Their Royal Highnesses The Duke and Duchess of Sussex are very pleased to announce that The Duchess of Sussex is expecting a baby in the Spring of 2019."
Their Royal Highnesses have 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.'
Last Friday, Eugenie shared two shy kisses on the West Steps of St George's Chapel with her new husband Jack after their lavish royal wedding ceremony.
The couple tentatively performed the kisses for the cameras on the steps, which were decorated with masses of autumn flowers and lined with Grenadier Guards.
After their afternoon reception in Windsor Castle, Jack drove Eugenie away in a silver DB10 Aston Martin sports car. The wedding drew in a peak of 3.9million on ITV.