Archduchess Helen, née Countess zu Toerring-Jettenbach, is the widow of His Imperial and Royal Highness Archduke Ferdinand of Austria, the granddaughter of H.I.H. Grand Duchess Elena Vladimirovna of Russia, and the second cousin of H.I.H. the Grand Duchess Maria of Russia, the Head of the Imperial House of Russia. Archduchess Helen is also the cousin of His Royal Highness Prince Philip, Duke of Edinburgh, husband of Queen Elizabeth II of Great Britain and Northern Ireland.

Among the guests attending the birthday dinner were Her Majesty Queen Elizabeth II, who has for many years been a close friend of Archduchess Helen, H.R.H. Prince Michael of Kent and his wife H.R.H. Princess Marie Christine of Kent, and his sister, H.R.H. Princess Alexandra of Kent, and H.R.H. Princess Barbara of Yugoslavia (née Princess of Liechtenstein).