The Prince of Wales paid a touching tribute to his father at the concert held to celebrate King Charles III’s coronation, saying: “Pa, we are all so proud of you.”

Taking to the stage in front of 20,000 people at Windsor Castle, Prince William praised the King’s dedication to the crown, as well as his environmental and charity work.

William said the King had “warned us of the risks to our planet’s health long before it was an everyday issue.”

He also highlighted the Prince’s Trust, established by his father, which he said “has supported over a million young people, many from disadvantaged backgrounds, to realise their ambitions.”

The heir to throne also made a sweet reference to his late grandmother Queen Elizabeth II, adding: “I know she’s up there, fondly keeping an eye on us.”

“She would be a very proud mother.”

William also made his own historic pledge as he thanked the millions who serve in the military, schools, NHS and local communities, saying: “I commit myself to serve you all. King, country and Commonwealth.”

The young royals almost stole the show from their father. In a heartwarming moment, Princess Charlotte attempted to get Prince George’s attention and pointed at William as he took to the stage.

By publicly calling Charles “Pa” and expressing the royal family’s pride in him, he echoed the speeches his father gave at the late Queen’s successive Jubilee concerts, when he referred to her as “Mummy”.

At his Golden Jubilee concert speech in 2002, Charles introduced his mother, as she stood beside him, with “Your Majesty … Mummy” and later said: “We feel proud of you.”

On Sunday in Windsor, William praised the King’s take on the natural world, saying: “He warned us of the risks to our planet’s health long before it was an everyday issue.”

His warm words were echoed by other guests, including Stella McCartney, who said she felt the King has a “true love and passion” for nature which has been shown through his work across his lifetime.

Ms McCartney, who has championed a vegan lifestyle and sustainable design throughout her career, said that she thought the King had “a true love and passion for nature and for mother earth and to safeguard that”.

William also heralded his father’s establishment of the Prince‘s Trust, adding: “It has supported over a million young people, many from disadvantaged backgrounds, to realise their ambitions.”

William continued: “Perhaps most importantly of all, my father has always understood that people of all faiths, all backgrounds, and all communities, deserve to be celebrated and supported.”

As William concluded his speech, he said: “God Save the King,” which was repeated loudly by the thousands in attendance.

Thousands gathered around Windsor Castle ahead of the concert. Earlier, William and Princess of Wales surprised crowds on the Long Walk, sharing laughs and drinks with well-wishers.

Here is the full text of William’s speech:

“Good evening Your Majesties. Good evening Windsor!

“A huge thank you to everyone for making this such a special evening.

“I want to say a few words about my father, and why I believe this weekend is so important.

“But don’t worry, unlike Lionel, I won’t go on all night long.

“As my grandmother said when she was crowned, coronations are a declaration of our hopes for the future.

“And I know she’s up there, fondly keeping an eye on us. And she would be a very proud mother.

“For all that celebrations are magnificent, at the heart of the pageantry is a simple message: Service.

“My father’s first words on entering Westminster Abbey yesterday were a pledge of service.

“It was a pledge to continue to serve.

“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.

“Take the natural world. He warned us of the risks to our planet’s health long before it was an everyday issue.

“Or the Prince’s Trust. It has supported over a million young people, many from disadvantaged backgrounds, to realise their ambitions.

“And, perhaps most importantly of all, my father has always understood that people of all faiths, all backgrounds, and all communities, deserve to be celebrated and supported.

“Pa, we are all so proud of you.

“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!”