Prince Guillaume attended his final plenary session at the Bock on Friday ahead of his new role this autumn.
The Council of State also took the opportunity to bid farewell to its outgoing vice-president - and one-time president - Christophe Schiltz, who will take on a new role as ambassador in Rome going forward.
Hereditary Grand Duke, Prince Guillaume, was appointed a member of the Council of State back in 2005, and will now leave the position as he is due to be sworn in as Lieutenant-Representative in October.
The position on the Council will therefore remain open until the Grand Duke names a Hereditary Grand Duke, who will then be nominated to the Council of State. Guillaume's son Prince Charles, aged 4, will therefore not necessarily automatically become an official councillor if he is named heir at the age of 18, but instead must go through the nomination process.
The above is foreseen in Article 4 of the law relating to the Council of State's organisation. Prince Guillaume himself only joined as a councillor at the age of 23. He will now be sworn in as Lieutenant-Representative for his father, Grand Duke Henri, on 8 October, 24 years after taking his oath as Hereditary Grand Duke. It will therefore take another 14 years for Prince Charles to assume this role.
The Council of State is yet to decide who will succeed Schiltz as vice-president.
