Queen Elizabeth Welcomes Second Great Grandchild!

Peter and Autumn Phillips stroll during a visit to the visitors centre with the rest of the Royal family at the Castle of Mey. August 2, 2010 Credit: Andrew Milligan - WPA Pool/Getty Images

Queen Elizabeth is a Great Grandma again!

Peter and Autumn Phillips welcomed their daughter, Isla Elizabeth Phillips, at the Gloucester Royal Hospital on Thursday, a spokesperson for the couple tells Us Weekly. Weighing in at 7 lbz., 4 oz., little Isla joins big sister Savannah, 15 months; thirteenth in line for the British throne, she is Queen Elizabeth's second great-grandchild.

Peter was present at his second daughter's birth, the rep added. The royal family is said to be "delighted" by Isla's arrival.

Peter, 34, is the son of Princess Anne and her first husband, Captain Mark Phillips; he and Autumn got married in May 2008 at Windsor Castle. His sister, Zara Phillips, wed rugby player Mike Tindall last summer at a wedding attended by all the royals -- including Prince William and Kate Middleton plus Prince Harry, who even sang karaoke at the bash.