The royal couple are due to become parents at some time in early 2021. They announced they were expecting a child in September, posting a photo of Eugenie holding a pair of baby slippers on Instagram.
The Instagram post by Eugenie came with the caption: “Jack and I are so excited for early 2021”.
The Queen and Prince Philip are understood to have been “delighted” by the news.
Princess Eugenie and Mr Brooksbank married in a ceremony in Windsor in October 2018.
Zara Tindall, daughter of Princess Anne, said she was expecting her third child with husband Mike Tindall earlier this month.
Mr Tindall, a former England rugby captain, revealed the news in an unusual way – on a podcast.
Speaking on his The Good The Bad and The Rugby podcast, he told co-hosts Alex Payne and James Haskell there was a “third Tindall on its way”.
The Queen and the Duke of Edinburgh are said to be “delighted” at the news.
Meanwhile, Christmas this year is due to be a quiet affair for the Royal Family amid the country’s coronavirus restrictions.
Already, the Queen has cancelled the annual royal Christmas celebrations at the Sandringham estate.
In addition, it is thought the new Tier 4 restrictions have thrown royal plans into even further disarray.
According to People magazine, Kate Middleton and Prince William have had to change their festive plans due to the sudden rule changes announced over the weekend.
Analysts speculated the Duke and Duchess of Cambridge, along with their children, had planned to celebrate Christmas with Kate’s family in Berkshire.
However, Berkshire has now been placed under Tier 4 measures which prohibit meeting people from other households indoors even over the Christmas or New Year period unless they are part of a support bubble.