The King and Queen are due to attend the ceremonial opening of the Welsh Parliament on Thursday.
This marks the first time King Charles will attend the event as King.
He and Queen Camilla previously joined the ceremony, which takes place following a Senedd election, in 2021 alongside Queen Elizabeth II.
He is scheduled to speak in the Siambr (Senedd debating chamber) alongside First Minister Rhun ap Iorwerth and Huw Irranca-Davies, the Llywydd (presiding officer).
Charles and Camilla will be welcomed to the Senedd by the Royal Navy Guard of Honour, who will give a Royal Salute.
At the ceremonial opening, a mace-bearer will lead a procession of Members of the Senedd (MSs) through the Senedd building into the Siambr.
Ahead of the opening, Mr Irranca-Davies said: “This ceremony marks the start of a new chapter in the Senedd’s history.
“It is a larger parliament, elected through a new electoral system designed to better reflect the diversity of views and experiences across our country.
“We are honoured that Their Majesties The King and Queen are here to share this moment with us.
“We will use this moment to celebrate the people, communities and culture of Wales and remind ourselves of the aspirations of those who put their trust in us to serve them in this seventh Senedd term.”
Alongside the speeches, the King’s Harpist, Mared Pugh Evans, will perform, and the Merched Plastaf Choir will sing O Gymru.
During their visit, Charles and Camilla will meet party leaders, members of the Welsh Youth Parliament, the chief executive and clerk of the Senedd, and the deputy presiding officer.
To commemorate the 60th anniversary of the Aberfan disaster, they will also meet Noah Jones, whose great-grandfather, Stephen Andrew, was a caretaker at Pantglas Junior School and helped save the lives of many children.
Charles, Camilla and Prince William are scheduled to visit the Aberfan Memorial Garden and the Aberfan and Merthyr Vale Community Centre on 21 October, before William visits a primary school to unveil the Aberfan Memorial Tree.
The trio will join survivors, bereaved parents and members of the community to pay tribute to the victims who lost their lives when a coal tip collapsed onto the village on 21 October 1966.
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