Ekaterina Ivanovna de Rusia

Princess Catherine Ivanovna of Russia was a great-great-granddaughter of Tsar Nicholas I of Russia and a niece of King Alexander I of Yugoslavia. She was the last member of the Imperial Family to be born before the fall of the dynasty. She was also second cousin of Prince Philip, Duke of Edinburgh, as Catherine's grandfather Grand Duke Konstantin Konstantinovich of Russia was younger brother of Prince Philip's grandmother Olga, Queen of Greece. Her relation to Prince Philip makes her a second cousin, once removed of King Charles III of the United Kingdom. She is also the grandmother of actor Sebastian Arcelus.