London - Queen Elizabeth II has become a great-grandmother for the second time, Buckingham Palace announced on Friday.
Isla Elizabeth Phillips was born on Thursday at the Gloucestershire Royal Hospital in Gloucester, southwest England, weighing 3.29kg.
She is the second child of Peter Phillips, 34, and his 33-year-old Canadian-born wife Autumn, following the birth of Savannah Phillips in December 2010.
Phillips is Queen Elizabeth's oldest grandchild and the son of her only daughter, Princess Anne, the Princess Royal.
Anne, 61, decided that her children would not bear royal titles and her son keeps a low profile, carrying out no royal duties.
Queen Elizabeth's press secretary said the monarch, her husband Prince Philip, Anne, her first husband Mark Phillips and the mother's family had all been informed and are "delighted with the news".
The new baby is 13th in line to the throne.
Queen Elizabeth, 85, is celebrating her diamond jubilee this year, marking her 60 years as a monarch.
Buckingham Palace would not confirm if the middle name had specifically been chosen as a tribute.
Members of the royal family attended a memorial service on Friday at Saint George's Chapel in Windsor Castle, west of London, commemorating the lives of queen Elizabeth, the queen mother, and princess Margaret.
Queen Elizabeth II's mother and sister died within weeks of each other 10 years ago.
The queen mother, the wife of king George VI, died peacefully in her sleep 10 years ago to the day, aged 101, while her daughter died the previous month aged 71, after suffering the third in a series of strokes.
Their remains were interred in the chapel, next to those of king George.