Princess Eugenie, the younger daughter of Prince Andrew and Sarah Ferguson, gave birth Tuesday to her first child.
Eugenie, 30, delivered her son at Portland Hospital in London, the same hospital where she was born.
Her husband, Jack Brooksbank, was present for the birth, according to Buckingham Palace.
The baby, whose name has not yet been announced, weighed 8 pounds, 1 ounce at birth, according to the palace.
Eugenie, whom the palace said is "doing well" post-delivery, shared a photo on Instagram of her newborn son's hand alongside a caption of blue heart emojis.
He is the first grandchild for Sarah and Prince Andrew, who stepped back from his royal public duties in 2019 due to heavy criticism over his relationship with convicted sex offender Jeffrey Epstein, who died in prison from an apparent suicide.
The baby is also the ninth great-grandchild for Prince Philip and Queen Elizabeth, who have four children and eight grandchildren.
MORE: Princess Kate, Duchess Meghan share something in common at Princess Eugenie's royal weddingEugenie and Brooksbank wed at St. George's Chapel at Windsor Castle in 2018.
The couple's son counts Prince Harry and Duchess Meghan's son, Archie, and Prince William and Duchess Kate's children, George, Charlotte and Louis, among his second cousins.
Eugenie's sister, Princess Beatrice, wed Edoardo Mapelli Mozzi, who has a school-age son, last year in a small, private ceremony amid the coronavirus pandemic.