Defence secretary Ben Wallace stood vigil at the Queen’s coffin as she lies in state in Westminster Hall.
Mr Wallace was joined by Scottish secretary Alister Jack, both dressed in the Royal Company of Archers uniform.
The two Cabinet ministers are members of the Royal Company of Archers, which functions as the sovereign’s bodyguard in Scotland.
They are part of a rotation of guards who will stand in vigil in 20-minute blocks until 6pm, when a new group will take over.
The Royal Family website states: “It performs duties at the request of The Queen at any State and ceremonial occasion taking place in Scotland.
“The Royal Company also provided a guard on vigil during Queen Elizabeth The Queen Mother’s lying-in-state.”
It continues: “The Royal Company’s most regular duty is to be in attendance at Her Majesty’s annual garden party at the Palace of Holyroodhouse.”
Another major duty for the Royal Company is attendance outside St Giles’ Cathedral, Edinburgh, at the services of installation of Knights of the Thistle.
After the Queen’s death at Balmoral in Scotland last week, Mr Wallace said the monarch had “dedicated her life to serving her nation”.
Mr Jack stated: “Her long reign was defined by hard work and dedicated public service, earning her the respect and devotion of her citizens.”
Mr Jack was appointed Scottish secretary and Mr Wallace was appointed defence secretary as part of Liz Truss’s new Cabinet.
Later this week, King Charles will stand vigil over the Queen’s coffin with his siblings.
On Friday evening, the King, Duke of York, Princess Royal and Earl of Wessex will stand in silence for 15 minutes at the four corners of the catafalque from 7.30pm.
The Queen’s children previously paid tribute to the Queen by staging a silent vigil around her coffin at rest in Edinburgh St Giles’ Cathedral.