Buckingham Palace says Queen Elizabeth has become a great-grandmother, thanks to Canadian Autumn Phillips.
Phillips, the Montreal-born wife of the queen's grandson, Peter Phillips, has given birth to a baby girl.
The baby is the Queen's first great-grandchild and is 12th in line to the throne.
A statement issued Thursday by the palace said Phillips gave birth at Gloucestershire Royal Hospital on Wednesday. The baby weighed eight pounds and eight ounces, and Peter Phillips was present at the birth.
"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," the palace's statement said.
The name of the child will be released later.
Peter Phillips, the son of Princess Anne, is the Queen's oldest grandchild. He married the former Autumn Kelly in May 2008 at Windsor Castle.