07/02/2007 AT 04:45 PM EDT
and his brother Harry are about gain a new cousin: Their uncle, Prince Edward, and his wife Sophie are expecting their second child in December.
"The Earl and the Countess [of Wessex] are both thrilled and excited," a palace spokesperson told the Associated Press. "The countess will continue with engagements as normal and take doctors' advice."
Edward, 43, is the youngest son of Queen Elizabeth II. He and the former Sophie Rhys-Jones, 42, already have a daughter, Lady Louise Windsor, born in November 2003. The family lives in Surrey.
The new arrival will be the eighth grandchild for the Queen and Prince Philip, who "are delighted with the news," a Buckingham Palace statement said.
Edward and Sophie wed at St George's Chapel in Windsor in June 1999 after meeting six years earlier at a summer tennis event. Sophie had suffered a life-threatening ectopic pregnancy in 2001 before becoming pregnant with Louise, according to the BBC