The Prince of Wales paid a touching public tribute to his father at the coronation concert, saying: “Pa, we are all so proud of you.”
William took to the stage at Windsor Castle as part of a night of celebrations featuring perfomances from stars including Katy Perry and Take That.
Speaking about his late grandmother, he said: “I know she’s up there, fondly keeping an eye on us” before telling the King: “She would be a very proud mother.”
The prince gave his speech in front of a crowd of 20,000 revellers at the star-studded Windsor Castle gala - and to an audience of millions watching at home - and praised the King’s dedication to “service” as well as his campaigning on green issues and support of diversity.
He described how his father’s first words on entering Westminster Abbey for his coronation – when he responded to the official greeting by a young chorister – were a pledge of service.
“It was a pledge to continue to serve,” William said.
“Because for over 50 years, in every corner of the UK, across the Commonwealth and around the world, he has dedicated himself to serve others, both current and future generations, and those whose memory must not be neglected.”
William also looked to his own future as a king, telling the audience: “I also want to express my pride and gratitude for the millions of people who serve, in the forces, in classrooms, hospital wards and local communities.
“I wish I could mention you all. Your service inspires us. And tonight we celebrate you too.
“I commit myself to serve you all. King, country and Commonwealth. God save the King!”
The younger members of the royal family - Princess Charlotte and Prince George - also played their part by dancing the night away to performances including Lionel Richie’s hit All Night Long and Take That’s anthems.
The princess also sang the words to Perry’s Roar and Firework, as the US singer took to the stage in a shiny gold metallic ball gown.
Like the rest of the 20,000-strong crowd, they wore flashing LED wristbands that lit up the night.
William’s speech was a highlight of a night which saw Top Gun star Tom Cruise tell the King - himself a trained pilot - “You can be my wingman any time”.
The concert hosted by Downton Abbey actor Hugh Bonneville saw the King’s life celebrated, from his role in the Armed Forces to his passion for the arts and his charitable work through the Prince’s Trust.
A host of celebrities including Tracey Emin and Richard E Grant recorded messages for Charles or highlighted little known facts about his life.
Katy Perry dedicated her song Firework to the King “and the work that we get to do together with the British Asian Trust and their Children’s Protection Fund”.
She told the crowd she got to “stay in Windsor Castle” – before joking: “No big deal.”
The King and Queen danced along to Take That’s performance of Shine as Princess George and his sister Princess Charlotte enthusiastically waved their Union flags.
In the final performance of the Windsor Coronation Concert, the band, who have not performed together for four years, ended with Never Forget – accompanied by the choristers of St George’s Chapel, Windsor Castle.
It brought the curtain down on a spectacular show - complete with drone displays and illuminated effects lighting up sites across the country - that began with the King’s words mixed into Pete Tong Ibiza Classics, featuring Vula and Jerub.
A fragment of his televised address to the nation the day after the Queen died was played as the performance began.
Charles said: “And wherever you may live in the United Kingdom, or in the realms and territories across the world, and whatever may be your background or beliefs, I shall endeavour to serve you with loyalty, respect and love, as I have throughout my life.”
