Elton John wowed audiences with a pre-recorded rendition of Your Song during the Party at the Palace concert for the Platinum Jubilee on Saturday.
Footage of the singer, 75, who was unable to perform in person due to his tour, delivering the ballad was projected onto Buckingham Palace itself while thousands of people watched on from the Mall.
The lyrics of the song were also projected while an orchestra accompanied him live.
The singer gave a romantic nod to the Cambridges with his performance - after choosing the song Kate and Prince William chose for their first dance at their wedding in 2011.
It was performed by the singer Ellie Goulding, a friend of Princess Eugenie's, at their wedding in 2011, and William could be seen singing along at the concert last night.
Love the royals? Sign up for the Mirror's daily newsletter to get all the latest news on the Queen, Charles, Kate, Wills, Meghan, Harry and the rest of The Firm. Click here to sign up
The musician first entered the Royal folds after striking up a friendship with Princess Diana. After her death in 1997, he worked up a version of 'Candle in the Wind' which he performed at her funeral.
Since then, he's reportedly served as an unofficial godfather to Prince William and Harry - especially when Harry courted trouble during his teenage years.
He also performed for the Sussexes at their wedding.
More than 30 members of her family appeared in the Royal Box at the specially built stage outside Buckingham Palace, ready to join the party.
The Duchess of Cornwall and Duchess of Cambridge were joined by the Queen's cousins, children and grandchildren.
The Earl and Countess of Wessex and their children, Lady Louise Windsor and Viscount Severn, were in attendance, as well as Princess Royal and Vice Admiral Sir Tim Laurence, Princess Beatrice and Edoardo Mapelli Mozzi, Princess Eugenie and Jack Brooksbank, Peter Phillips and his children Savannah and Isla, and Zara and Mike Tindall.
The Duke and Duchess of Sussex didn't attend as it was their daughter's Lilibet Mountbatten- Windsor's first birthday.
Today, the Prince of Wales said he hopes “bickering” does not return after a feeling of “togetherness” across the nation over the Platinum Jubilee weekend.
Charles and Camilla mingled with guests at the Big Jubilee Lunch in The Oval.
Gemma Snow, from the Eden Project, was sitting next to Charles at the lunch for a few minutes and said he talked about “keeping that togetherness going”.
