Edoardo, 38, is already a doting father to his son Christopher, also known as Wolfie, from his relationship with ex-partner Dara Huang.
The royal couple is due to welcome their baby in autumn, just over one year after their secret lockdown wedding.
On Thursday, Beatrice’s sister, Princess Eugenie shared her delight that the couple were welcoming a child together and posted some unseen photos from their wedding last July.
Responding to Eugenie’s post, Edoardo wrote: “Thank you. So thrilled our little family is growing.”
Buckingham Palace announced the pregnancy on Wednesday morning, with a statement written on behalf of the Queen, which read: “Her Royal Highness Princess Beatrice and Mr Edoardo Mapelli Mozzi are very pleased to announce that they are expecting a baby in autumn of this year.
“The Queen has been informed and both families are delighted with the news.”
Beatrice’s baby will be the Queen’s 12th great-grandchild following the arrival of Prince Harry and Meghan Markle‘s second child in the summer