Soldiers from The King's Troop Royal Horse Artillery have been deemed "fit for role" for their upcoming guard duties at Windsor Castle.
The unit passed an inspection by senior staff from the Household Division at Wellington Barracks on Wednesday.
Lieutenant Colonel Guy Stone, The Brigade Major of the Household Division, was one of those inspecting the troops in Woolwich.
The soldiers will take on the role as the Windsor Castle Guard, replacing the Foot Guards, on 15 March for two weeks.
It is the first time the Royal Horse Artillery has been tasked with such role since 2008.
"We are extremely privileged and honoured to have this opportunity of providing the Guard for Windsor Castle," said Commanding Officer, Major Victoria Flood.
"This not being the soldiers’ primary job, they have worked incredibly hard preparing themselves for this public duty whilst still training for their normal equestrian ceremonial role."
The move is part of the British Army's new policy of integration - aimed at making soldiers work more closely together and allowing them to understand roles and duties undertaken by other units.
Gunner Jessica Bartlett told Forces News: "With us taking over as the Windsor Castle Guards, it allows the other guards to have a bit of a break and go do what they need to do and allow them to be free for different tasks that they need to go and do."
The King's Troop Royal Horse Artillery has been rehearsing the complex ceremonial moves and order of commands since Christmas.
Gunner Bartlett said the weather over the past few weeks has made their rehearsals quite challenging.
"It's been raining all week, it's been really cold and the uniform gets very wet," she explained.
However, she said it has been "really good fun" and the unit has seen it as "a learning curve".
The soldiers will be supported throughout their duties in Windsor with music by the Bands of the Household Division.