Peter and Autumn Phillips and daughter Savannah
03/30/2012 AT 12:30 PM EDT
The Queen is a great grandmother once again!
Her grandson Peter Phillips
and wife Autumn welcomed a baby girl on Thursday at Gloucestershire Royal Hospital, according to Buckingham Palace.
"Isla Elizabeth Phillips weighed 7 lbs. and 4 oz. and Mr. Peter Phillips was present at the birth," the Palace said in a statement Friday.
The newborn will be the 13th in line to the British throne, after her sister Savannah, 15 months.
According to the Palace, the Queen and her family "have been informed and are delighted with the news."
Peter, the son of Princess Anne
and brother of Zara, married Autumn in 2008.