Units Prince Harry served with on his two tours of Afghanistan will play a vital role when their brother in arms marries Meghan Markle.
Members of regiments and units with a special relationship with the prince will provide ceremonial support at the wedding at St George's Chapel and during the carriage procession that follows.
"Prince Harry and Ms Meghan Markle are pleased that members of the Armed Forces will play such a special role in their Wedding," Kensington Palace said in a statement.
"The Military, and these units in particular, hold a great significance for Prince Harry and the couple are incredibly grateful for their support."
Among the soldiers lining the streets within Windsor Castle will be soldiers from the 3 Regiment Army Air Corps and The Royal Gurkha Rifles - the units Harry served with on his two tours of Afghanistan.
During the decade he served in the Army, the prince rose to the rank of Captain and now serves as the Commodore-in-Chief of the Royal Navy Small Ships and Diving, Captain General of the Royal Marines and Honorary Air Commandant of RAF Honington.
Members from these units, the Windsor Castle Guards and the 1st Battalion Irish Guards will also defend the streets on the day of the May 19 nuptials.