The Queen's Gurkha Engineers (QGE) are mounting their first Queen's Guard at Buckingham Palace.
Ordinarily, the soldiers are electricians, plumbers and bricklayers, but for the past few months, they have been tasked with guarding the royal family.
The regiment carried out the duty during Gurkha 200 celebrations in 2015, but never as an actual deployment for a lengthy period.
The Gurkha Guardsmen provide centuries at Buckingham Palace and St James’ Palace from 8am to 8pm and are standing guard at the Tower of London and Windsor Castle.
Before the Gurkhas took command, they had a crash course in drill from the Scots Guards. Sapper Susan Narbu Limbu said:
"I enjoy it, but at first it was hard, because you stand there for two hours, without any movement."
Another challenge for the Queen's Gurkha Engineers Quartermaster, Captain Gary Forsey, was getting the uniforms to fit:
"Gurkhas are not the same height as a standard British soldier... So I had a logistic nightmare sourcing and tailoring.
"None of this kit is issued for the guys. Grey coats come for guardsman size, not for Gurkha size.
"It was an interesting challenge but as you can see, they look fantastic."
While undertaking the Queen's Guard, the Gurkhas wear Kilmarnock hats on parade and march at a faster rate of 140 paces a minute.
They also carry their rifles at 'the trail' - down by their side - rather than on their shoulders like the rest of the Army. Ensign of the Guard will not carry a regimental flag, due to the QGE's links with the Royal Engineers.
Each Gurkha carries a kukri instead of a bayonet on parade, which are drawn for inspection before the Changing of the Guard at Wellington Barracks.
The origins of the Changing of the Guard date back to 1660 and is carried out by troops on active duty.
The Queen's Gurkha Engineers will be providing the Queen's Guard and Windsor Guard until 12 April.
Listen: Forces Radio BFBS' Heather Lewis spoke to Lieutenant Simon Smith, who explained how they prepared for the role.