Peter Phillips - the son of Princess Anne and her first husband Captain Mark Phillips - and his Canadian-born wife Autumn have announced the birth of their daughter, who is yet to be named.
The baby - who was born on Wednesday (29.12.10) at Gloucestershire Royal Hospital - is a first child for Peter and Autumn, first grandchild for Princess Anne and the first great-grandchild for Queen Elizabeth and Prince Philip, who are said to be "delighted" at the happy news.
A statement from Buckingham Palace 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."
Weighing 8lbs, 8oz, the baby girl has now jumped ahead of her aunt, Zara Phillips - who recently announced her engagement to rugby ace Mike Tindall - to become eighth in line for the British throne.
Her birth means Queen Elizabeth has become the first monarch to be a great-grandparent since Queen Victoria over a century ago.