Isla Elizabeth Phillips, born Thursday, weighed in at 7 pounds and 4 ounces (3.29 kilograms).
She will be 13th in line to the British throne, after her older sister Savannah.
The palace said Friday that the 85-year-old queen, her husband the Duke of Edinburgh, Princess Anne and Autumn’s family are delighted by the news.
Peter Phillips is the son of Princess Anne. He married Montreal-born Autumn in May 2008.
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