Prince Charles delighted royal well-wishers when he referred to the Queen as "Mummy" during a moving speech at a star-stunned concert to celebrate the Platinum Jubilee.
The heir to the throne joined the Duke and Duchess of Cambridge, Prince George, Princess Charlotte, Prince Louis and the Tindalls to watch BBC's Party at the Palace.
Closing off the evening's entertainment, which included performances from Sir Elton John, Diana Ross, Sir Rod Stewart, Alicia Keys and Duran Duran, he thanked the Monarch for her 70 years of service.
He said: “Your Majesty, Mummy. You have been with us in our difficult times. And you bring us together to celebrate moments of pride, joy and happiness. You have met us and talked with us. You laugh and cry with us and, most importantly, you have been there for us, for these 70 years."
It's far from the first time Charles has used the affectionate term for his mum in public, including at the Diamond Jubilee concert.
But perhaps the most iconic occasion was when he called her 'Mummy' back in 2018 during her 92nd birthday celebrations at the Royal Albert Hall - and it was all down to her reaction.
Keep up to date with all the latest from the Queen's Platinum Jubilee on our live blog.
Starting his speech, he again said "Your Majesty, Mummy" to huge cheers and applause from the crowd.
The Queen, who was standing next to him on stage dressed in a stunning yellow outfit with a pearl necklace, could be seen rolling her eyes to the ceiling before breaking into a smile.
The Monarch was joined by other members of her family, including Prince William, Sophie Wessex and Princess Beatrice for the event - and they were all seen laughing along as well.
Prince Philip also paid tribute to his father, Prince Philip, during his Platinum Jubilee speech.
He said: “You pledged to serve your whole life – you continue to deliver. That is why we are here. That is what we celebrate tonight.
“The scale of this evening’s celebration – and the outpouring of warmth and affection over this whole Jubilee weekend – is our way of saying thank you – from your family, the country, the Commonwealth, in fact the whole world.
“On behalf of us all, I wanted to pay my own tribute to your lifetime of selfless service.
“Your family now spans four generations. You are our Head of State. And you are also our mother.”
The Duke of Cambridge also took to the stage and hailed the Platinum Jubilee concert as full of “optimism and joy” as he praised the Queen for her “hope” in the future of the planet.
He received a loud cheer from the crowds when he mentioned how the Queen was almost 100, and how during her lifetime she had seen great technological changes.
During the evening, the Queen delighted fans with a surprise comedy sketch with Paddington Bear during which she revealed she shared his love of marmalade sandwiches.
After enjoying a slightly disastrous afternoon tea, the beloved bear offered the Monarch a sandwich but she said she always keeps an emergency stash in her trademark handbag.
The head of state and her furry guest introduced the opening act Queen by tapping out their song We Will Rock You on china teacups.