The Queen has fulfilled the ambition of her late "papa", becoming colonel-in-chief of his former regiment.
Queen Camilla marked her new honorary role with the Royal Lancers (Queen Elizabeths' Own) by inviting Michael de Burgh to Clarence House.
Mr de Burgh, a Second World War veteran and stalwart of the regiment, celebrates his 100th birthday on 11 June.
The Queen shared some of her father's wartime stories and presented him with the Buchan Medal in recognition of his support for the Royal Lancers over the decades.
Mr de Burgh served with the 9th Lancers, which was later amalgamated with the 12th Lancers – the regiment of her late father, Major Bruce Shand.
Camilla told him: "My father just longed for me to be associated with this regiment, and here I am."
She presented a copy of Previous Engagements, Major Shand's wartime memoirs, to Mr de Burgh who was surrounded by his children and grandchildren.
"Here's a copy of my papa's book which I believe you haven't read – now you've got it," she said before she helped them cut a chocolate birthday cake.
The Royal Lancers, an armoured reconnaissance regiment, was formed in 2015 when the 9th/12th Royal Lancers and The Queen's Royal Lancers were amalgamated, and the words "Queen Elizabeths' Own" were later added to recognise the link between them, Queen Elizabeth and the Queen Mother.
Major Shand was awarded the Military Cross in 1940, during the retreat to Dunkirk, and again in 1942 for his efforts in North Africa, where he was wounded and taken prisoner.
He died in June 2006 aged 89.
Mr de Burgh, from Sussex, worked in finance and later ran a trout farm.
He came to know Camilla's father socially after the war and said about of him: "He was a lovely man, nice to everybody."
Mr de Burgh was wounded just 14 days before the Allies' victory in Europe was declared. His gunner was the last member of the 9th Lancers to die during the war.
He joked about his injuries, saying a sergeant told him at the time: "What a mass of blood you are, sir."
Lieutenant Colonel Will Richmond, Commanding Officer of the Royal Lancers, said about the Queen's appointment: "We really are delighted."
He added: "To quote someone more famous than me, 'it's been a long time coming' and we have longed hoped for it and I understand Her Majesty has been keen to achieve it for a long time."
Queen Camilla is the patron of Forces News' parent charity, BFBS.