The Scottish First Minister is one of 200 privy counsellors summoned to attend the Accession Council at St James’s Palace in London and take part in King Charles’s first Privy Council.
The ceremony is expected to take place at 10am, Buckingham Palace confirmed.
It will be televised for the first time, and camera crews will be given permission to enter the State Apartments to capture the proceedings.
Also for the first time, a Principal Proclamation will be read in public by the Garter King of Arms from the balcony overlooking Friary Court at St James’s, at around 11am.
It will be followed by a flurry of Proclamations around the country, with the second one in London at the Royal Exchange at midday on Saturday, and further Proclamations in Scotland, Northern Ireland and Wales at midday on Sunday.
Union Jack flags are expected to fly at full mast from the Principal Proclamation at St James’ Palace after the proclamations held in Scotland, Northern Ireland and Wales.
They will then return to half-mast in mourning for the death of Queen Elizabeth II.
The Accession Council is usually held within 24 hours of the death of a sovereign, however, it is being staged a day later for King Charles because the news of his mother’s passing didn’t come until early evening.
This meant that there wasn’t enough time to set the plans in motion for the following morning.
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UK commons leader Penny Mordaunt and MP Dominic Raab also arrived at St James’s Palace to attend the Accession Council on Saturday morning.
The Metropolitan police have announced plans to launch their well-rehearsed plans across the capital, following the passing of Queen Elizabeth II.
The public will see additional officers posted outside key locations, including transport hubs, Royal Parks and outside Royal residences in London.
Road closures are also being established at a number of locations in Westminster.
Tom Tugendhat, Harriet Harman, Yvette Cooper, David Lammy, John Sentamu, Peter Mandelson, Michael Howard, David Lidington and the former Archbishop Rowan Williams all arrived at St James’ Palace.
Jacob Rees-Mogg also arrived at the palace, wearing a top hat and tales, alongside Iain Duncan Smith.
Other notable figures include Nick Clegg, Ed Miliband and Dominic Raab, who are also on the Accession Council.