The British royal, who is 30, made the announcement in an adorable Instagram post of the couple's hands intertwined with a pair of fuzzy teddy bear baby shoes.
"Jack and I are so excited for early 2021....👶🏻," Prince Andrew 's youngest daughter captioned the photo.
Buckingham Palace also confirmed the happy news in an announcement released early Friday.
"👶 Her Royal Highness Princess Eugenie and Mr Jack Brooksbank are very pleased to announce that they are expecting a baby in early 2021," the official royal family's Instagram account reads underneath a photograph of the couple on their wedding day. "The Duke of York and Sarah, Duchess of York, Mr and Mrs George Brooksbank, The Queen and The Duke of Edinburgh are delighted with the news."
William and Kate’s son, Prince George, played page boy while his little sister, Princess Charlotte, served as one of Princess Eugenie's six bridesmaids.
The couple dated for seven years before becoming engaged in January 2018. Brooksbank proposed during a holiday trip to Nicaragua.
Eugenie's pregnancy announcement comes just months after her older sister, Princess Beatrice, 32, wed Edoardo Mapelli Mozzi in a private ceremony in Windsor. The ceremony was attended by a "small" group of guests due to the coronavirus pandemic and included Queen Elizabeth, and Prince Philip, the Duke of Edinburgh.
This will be the first grandchild for Eugenie’s parents, Prince Andrew and Sarah Ferguson, and Queen Elizabeth and Prince Philip's ninth great-grandchild.
Fox News' Sasha Savitsky contributed to this report.