She may be at an age where many have been long retired, but the Queen shocked royal fans with a previously unannounced visit to Britain's domestic security agency MI5's head office in London.
Dressed in a smart plum coat and matching hat, the 93-year-old monarch was given a tour of the agency's private museum and even learnt how her beloved father, King George VI used his own skills to deceive the Nazis during World War II.
Accompanied by Director General Andrew Parker, the Queen looked at a number of artefacts relating to the MI5 D-Day operations that focused on the brave double agents who helped to deceive the Nazis over the site of the Second World War D-Day landings.
But in what was no doubt a personal moment for the Queen, she was also told of how her father played a significant role for his country by distracting the enemy with a visit to a fake oil storage depot in Dover built by Shepperton film studios on behalf of the War Office.
The Queen also shared a heartfelt message of thanks to the workers at MI5, applauding them for the "tireless work" they do to defend Britain.
"I would like to take my visit here today as an opportunity to thank you all for the tireless work you do to keep our country safe. I am always struck by the remarkable resolve with which you carry out your vital role," she said in her address.
"There will no doubt continue to be significant threats and challenges ahead. But on each of my visits to MI5, I have been impressed by the way that you have adapted to the changing threats to our nation. Whether responding to the threats from the Nazis or the Cold War, domestic terrorism or the cyber sphere, you have always demonstrated the utmost commitment to your motto: 'Regnum Defende'".
"Because of the nature of your work, it is without public recognition, so it is on behalf of the country that I say to you all, thank you."
This hasn't been the only occasion this year when the Queen has thought of her late father.
In early February, the royal retraced King George VI's footsteps while on a public engagement at a pumping station in Wolferton in Sandringham and when said station was first opened 72 years ago, it was her father who was there for the big reveal.
Posting to the official Royal Family social media accounts, the Palace wrote: "Today, The Queen will open Wolferton's new Pumping Station, 72 years after her Father, King George VI, opened the original station on 2 February 1948."
"Wolferton Pumping Station was opened shortly after the Second World War to enable the surrounding marshland to be brought into full production."
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Whilst the Queen has returned to her London residence at Buckingham Palace, she spends most of the winter months at her Sandringham estate.
Indeed, it's a place she and her father loved and it's where she traditionally stays on the anniversary of her ascension to the throne and this year marks a whopping 68 years.
But the day is also a sad occasion as it's the anniversary of King George's death and the Queen usually spends it in private with her husband, Prince Philip.