The Prince of Wales has paid a touching public tribute to his father the King during the coronation concert at Windsor Castle, saying “Pa, we are all so proud of you.”

Heir to throne William also made an emotional reference to his late grandmother Queen Elizabeth II after taking to the stage, adding: “I know she’s up there, fondly keeping an eye on us.”

He told his newly crowned father Charles: “She would be a very proud mother.”

The prince delivered his speech in front of a crowd of 20,000 revellers at the star-studded gala where the royal family gathered to watch singers such as Katy Perry, Olly Murs, Lionel Richie and Take That.

He praised the King’s decades of service, his campaigning on green issues, Prince’s Trust charity and celebration of diversity and support for people of all backgrounds, communities and faiths.

William, a future king himself, 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.”

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 concert, 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.”

Prince William's tribute to the late Queen Elizabeth II

Speaking of the late Queen, Prince William, said: “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.”

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.”

He 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.”

The future King 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.”

In his final comments, William told Charles: “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!”