Princess Eugenie is expecting a baby, Buckingham Palace has announced.
The Queen and Duke of Edinburgh are said to be "delighted" by the news their granddaughter is pregnant.
Eugenie and husband Jack Brooksbank wed at St George's Chapel, Windsor Castle, in October 2018.
Eugenie, the daughter of the Duke of York and his ex-wife Sarah, Duchess of York, is due to give birth early next year, the palace said.
Buckingham Palace said in a short statement: "Her Royal Highness Princess Eugenie and Mr Jack Brooksbank are very pleased to announce that they are expecting a baby in early 2021.
"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."
The baby will be a ninth great-grandchild for the Queen and the Duke of Edinburgh, following the arrival of their eighth – the Duke and Duchess of Sussex's son Archie Mountbatten-Windsor.
Eugenie's parents, Andrew and Sarah, will become grandparents for the first time.
The baby boy or girl will be born 11th in line to the throne.
But although their mother is a princess, their father has no title and so the child will be born down a female line of the royal family – meaning they will be plain Master or Miss Brooksbank.
They will not be an HRH nor hold a title, unless the Queen decides to intervene and give Mr Brooksbank – who is European brand manager for Casamigos Tequila co-founded by George Clooney – an earldom or issue a Letters Patent amending the rules.
Eugenie, 29, posted on Instagram at the start of 2019 expressing her anticipation at what was to come in the year ahead, prompting speculation then that she might be pregnant.
Alongside one of the couple's engagement photos, Eugenie wrote: "What a year it's been since then and how exciting for 2019."
Eugenie and Jack married in a glittering ceremony in the Gothic surroundings of St George's Chapel in front of royal and celebrity guests on October 12, 2018.
The princess wore a 1950s-inspired gown by Peter Pilotto and Christopher De Vos, with a low back designed to show her scar from scoliosis surgery she underwent as a child.
The couple took a covered horse-drawn carriage ride through Windsor on the blustery autumn day, and continued their celebrations throughout the weekend at the York family home, Royal Lodge in Windsor Great Park.
It was at Eugenie and Mr Brooksbank's wedding that Harry and Meghan shared the news with the royals that the duchess was pregnant.
Princess Eugenie Victoria Helena of York was born on March 23 1990 at the exclusive Portland Hospital in London.
She could follow her mother's lead and have her baby at the Portland, where older sister Princess Beatrice was also born and where the Duchess of Sussex had Archie – or she might even opt for the Lindo Wing at St Mary's Hospital in Paddington like the Duchess of Cambridge.
Eugenie is a director at the contemporary art gallery Hauser & Wirth in London.
Her romance with Stowe-educated Mr Brooksbank began after they fell in love at first sight on a ski trip near Verbier in Switzerland.
They dated for around seven years before he proposed.
Sarah, Duchess of York, who was cast out from the Windsors amid her "toe sucking" scandal in the 1990s, has been gushing in her admiration of Eugenie's husband.
She described the couple as "pure harmony" together, adding: "We love Jack and I am so excited to have a son, a brother and a best friend."
The duchess previously spoke of her hopes of becoming a grandmother, saying she would be "excellent" in the role.
She added: "I used to write children's books, and I am a child. I haven't grown up."