Princess Beatrice and her husband Edoardo Mapelli Mozzi’s second child will be born 11th in line to the throne.
The royal baby will be a little brother or sister for the couple’s three-year-old daughter Sienna, who is currently 10th in line to the throne.
Beatrice’s younger sister Princess Eugenie sits in 11th place as it stands, but she will move down to 12th place once the baby is born.
The late Queen’s granddaughter, 36, and Mr Mozzi, 40, are preparing to welcome a new addition to their family in early spring.
The baby will also be a sibling to Mr Mapelli Mozzi’s son and Beatrice’s stepson, eight-year-old Wolfie, who is not in the line of succession.
Their new child will not be an HRH (His or Her Royal Highness) or a Prince or Princess – and will also not require the monarch’s permission to marry.
For hundreds of years, the Royal Marriages Act 1772 meant descendants of George II had to seek the sovereign’s consent before they wed, otherwise their marriages were deemed invalid.
But this law was repealed through the Succession to the Crown Act 2013, which restricted the consent to just the first six people in the line of succession.
As the new baby is 11th in line, they will not at present need to seek a monarch’s approval to wed.
George III, George II’s grandson, had ordered the 1772 Act after his younger brother, the Duke of Cumberland, secretly married Lady Anne Horton, deemed to be a highly disreputable widow of a commoner.
Beatrice is the eldest daughter of the Duke of York and his ex-wife Sarah, and the new baby will be the Yorks’ fourth grandchild.
He or she will also be the 14th great-grandchild of the late Queen Elizabeth II, and the second to be born since her death in 2022, following the arrival of Eugenie’s second child Ernest last year.
The Mapelli Mozzis’ daughter Sienna, whose has the second name Elizabeth in honour of the late Queen, was born at the Chelsea and Westminster Hospital, weighing 6lb 2oz, on September 18 2021.
Beatrice married millionaire property tycoon Mr Mapelli Mozzi in a secret lockdown wedding in 2020 attended by her grandparents the Queen and Prince Philip, Duke of Edinburgh, after her planned ceremony was postponed because of the pandemic.
Known as Edo, Mr Mapelli Mozzi is the son of former Olympic skier Count Alessandro Mapelli Mozzi and Nikki Williams-Ellis.
His son Christopher Woolf, nicknamed Wolfie, was born in 2016 to his then-girlfriend, American architect and designer Dara Huang.
Beatrice has described Wolfie as her ‘bonus son’ and he joined the Mapelli Mozzis at Kate’s Together At Christmas carol service in Westminster Abbey last December, holding hands with his stepmother as he arrived.
The princess, who is not a full-time working royal, is an adviser for Afiniti, an artificial intelligence software firm, and a co-founder of The Big Change Charitable Trust.
She has a number of royal patronages including the Forget Me Not Children’s Hospice, the Teenage Cancer Trust and the Helen Arkell Dyslexia Centre.
Buckingham Palace said in a statement: ‘Her Royal Highness Princess Beatrice and Mr Edoardo Mapelli Mozzi are very pleased to announce that they are expecting their second child together in early spring; a sibling for Wolfie, aged eight, and Sienna, aged three.
‘His Majesty The King has been informed and both families are delighted with the news.’