The Queen has become a great-grandmother for the second time, Buckingham Palace said.
Isla Elizabeth Phillips was born on Thursday at the Gloucestershire Royal Hospital, Gloucester, to Peter Phillips and wife Autumn, weighing 7lb 4oz.
She is a second daughter for Mr Phillips, who was present at the birth, and his wife. Her older sister Savannah was born in 2010.
The Queen's press secretary said: "The Queen, the Duke of Edinburgh, the Princess Royal, Captain Mark Phillips and Autumn's family have been informed and are delighted with the news."