Princess Margaret Blows a "Squeaker" Attends Fancy Dress Party with Sister - Princess Margaret Rose blows a "squeaker" at the party.Background (left) is Princess Elizabeth.Princess Elizabeth and Princess Margaret Rose attended a children's fancy party at the home of Viscountess Astor in St. James' Square, London.Both the Princess were historical costumes of the Elizabeth an period.They mixed freely with the 70 other young guests, who included the children of the American Ambassador, inflated balloons, joined in the games and amused themselves enormously. March 07, 1939.