While the royals rarely indulge in public displays of affection, Prince Philip once made the Queen blush with one of his compliments!
Royal author Ingrid Seward recalled an anecdote about the monarch during a dress fitting with couturier Ian Thomas.
WATCH: The Queen 'flushed scarlet' after compliment from Prince Philip
Ms Seward told Channel 5's documentary Secrets of Royal Dressmakers: "When [Ian Thomas] was doing the hem, Prince Philip walked through the Queen's dressing room and said, 'hmm, nice dress'.
"And the Queen flushed scarlet and I always remember him telling me that story.
"She was just so thrilled to get a compliment from her husband, who's normally so brusque and offhand."
Princess Elizabeth and Prince Philip on their wedding day in 1947
During a speech to mark the couple's 50th wedding anniversary in 1997, the Queen said of her husband: "He is someone who doesn't take easily to compliments but he has, quite simply, been my strength and stay all these years, and I, and his whole family, and this and many other countries, owe him a debt greater than he would ever claim, or we shall ever know."
Twenty years later, Buckingham Palace also released a series of official portraits to mark Her Majesty and the Duke's platinum anniversary to mark 70 years of marriage.
The Queen and Prince Philip on their 60th wedding anniversary in 2007
It's set to be another milestone year for the pair as the Queen prepares to celebrate her 95th birthday in April.
The monarch's birthday parade – Trooping the Colour – is due to go ahead in June as planned, with a senior aide telling The Sunday Times: "The current plan is for the Queen's birthday parade to go ahead in London as normal, with the acceptance that it may need to be adapted or scaled back depending on what guidelines are in force at the time. But the aspiration and the ultimate desire is to make it happen."
Meanwhile, Prince Philip will mark his 100th birthday on 10 June.
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