King Charles is the new monarch following the death of his mother, Queen Elizabeth II, on Thursday.
Her death sparks a ten-day period of mourning, leading up to her funeral, which is expected to take place on Monday, September 19.
On Saturday, The Accession Council will meet at 10am at St James’s Palace in London to formally proclaim Charles III as the new sovereign.
First, the Privy Council will gather without the King to proclaim the new monarch and arrange business relating to the proclamation.
Charles will then hold his first Privy Council, accompanied by Camilla – the new Queen Consort – and William, who are also Privy Counsellors, and makes his personal declaration and oath.
The first public proclamation of the new sovereign will be read in the open air from the Friary Court balcony at St James’s Palace by the Garter King of Arms.
Proclamations will be made around the city and across the country.
Union flags go back up to full-mast at 1pm and remain there for 24 hours to coincide with the proclamations before returning to half-mast.
Charles will also hold audiences with the Prime Minister and the cabinet.
Meanwhile, thousands of mourners are expected to gather in Edinburgh and London to pay their respects.
STV News is now on WhatsApp
Get all the latest news from around the countryFollow STV News
Follow STV News on WhatsApp
Scan the QR code on your mobile device for all the latest news from around the country