The Prince of Wales was all smiles at the Commonwealth Day service as he made his first public appearance since his wife admitted to “editing” their Mother’s Day picture.

The event celebrating the family of nations is a major fixture in the royal year but has been overshadowed by the Princess of Wales’ statement she manipulated a family photo released on Sunday.

The prince, who was spotted with Kate in his car while in London, arrived at Westminster Abbey alone before the Queen, and was greeted by the Dean of Westminster David Hoyle, shaking his hands with the senior cleric.

William was introduced to the Abbey’s Chapter, or governing body, shaking their hands as he made his way along the line of clergy.

Missing was the King, who continues to receive treatment for cancer, but in his annual address to the family of nations, he pledged to continue to serve the Commonwealth “to the best of my ability”.

Since his cancer diagnosis was announced on February 5, Charles has postponed all public-facing duties but is continuing with behind-the-scenes work on his red boxes of state papers and holding some in-person meetings.

His address highlighted how “diversity” was the Commonwealth’s core “strength”, and the union of 56 member countries was a “precious source of strength, inspiration, and pride” to him.

Charles said in the video message: “In recent weeks, I have been most deeply touched by your wonderfully kind and thoughtful good wishes for my health and, in return, can only continue to serve you, to the best of my ability, throughout the Commonwealth.”

Camilla and William were joined by the Duke and Duchess of Edinburgh, the Princess Royal, the Duke and Duchess of Gloucester and the Duke of Kent.

The royals warmly greeted each other before they lined up for the procession to their seats.

The prince gave Edward a friendly pat on the arm and a kiss on both cheeks, before standing in conversation with his aunts Anne and Sophie and uncle.

As Camilla, dressed in a turquoise coat and hat, approached, William was seen to say “hello” to his stepmother before moving forward to kiss her on both cheeks.

They smiled and chatted for a few moments as they stood side by side at the head of the royal party.

Camilla looked back, as if to check the other members of the monarchy were in place and when the national anthem began, all the royals sang.

The annual celebration will draw on the theme of resilience at a time when the royal family has faced a barrage of health troubles.

Among the 2,000 guests were Commonwealth Secretary-General Baroness Scotland, the president of Malta, foreign ministers, high commissioners, senior politicians and dignitaries from across the Commonwealth and faith leaders as well as schoolchildren and young people from throughout the UK.

The service, which marked the 75th anniversary of the family of nations, featured performers from across the Commonwealth including a dance troupe from Uganda that tickled the royals.

The front row of Camilla, William, Edward, Sophie and Anne smiled then laughed as the youngsters, who featured on Britain’s Got Talent, twirled and jumped.

Protesters from the Republic campaign group had earlier gathered outside, near the abbey.

The demonstrators carried bright yellow placards bearing the slogan “Down with the Crown”.

Graham Smith, chief executive of Republic, said: “The royals need to stop using the Commonwealth as a vehicle for their own PR.

“The platitudes we hear from Charles and Camilla only serve to paper over serious concerns about human rights abuses and a lack of democracy in many Commonwealth countries.”

He added: “The royal family funded, promoted and defended slavery for centuries, and then presided over an empire that caused untold damage to people’s lives that continues to have an impact to this day.

“Reparations are a reasonable demand. As a hereditary monarch, Charles can hardly argue that what his ancestors did has nothing to do with him.”