Prince George and Princess Charlotte in surprise Jubilee visit to Cardiff Castle

Prince George and Princess Charlotte have made a surprise visit to Wales as part of the Jubilee celebrations.

The royal youngsters joined their parents the Duke and Duchess of Cambridge to meet entertainers staging a show in honour of the Queen at Cardiff Castle.

The Cambridges were set to learn about the lighting, sound, and visual effects for the show, watch rehearsals and meet the hosts, Aled Jones and Shan Cothi.

Stars arrive for Jubilee concert; Charles to speak about Queen - live updates

Missing was four-year-old Prince Louis, who stole the show as he pulled faces and covered his ears when he appeared on Buckingham Palace's balcony after the Trooping the Colour ceremony on Thursday.

The visit came ahead of the star-studded Jubilee concert at Buckingham Palace where Prince Charles and Prince William will address the crowds.

The Queen is unable to attend the event herself after it was announced she would miss Derby Day at Epsom Downs racecourse on Saturday.

The 96-year-old is a huge horse-racing fan but skipped the 243rd running of the Derby because of "episodic mobility problems" which also forced her to miss Friday's thanksgiving service at St Paul's Cathedral.

She watched the racing event on television at Windsor Castle.

Star-studded concert

The concert, which will be attended by 22,000 people and televised live, will feature Alicia Keys, Nile Rodgers, Andrea Bocelli, Duran Duran, Hans Zimmer, Ella Eyre, Craig David, Mabel, Elbow, George Ezra and the UK's recent Eurovision star Sam Ryder.

It will see the return of rock band Queen, whose guitarist Brian May performed on the roof of Buckingham Palace for the previous Party at the Palace in 2002. They will be accompanied by singer Adam Lambert.

There will be appearances by Sir David Attenborough, Stephen Fry, US Open winner Emma Raducanu, David Beckham, Paralympic swimmer Ellie Simmonds, Dame Julie Andrews and members of the Royal Ballet.

Set on three stages in front of the palace, the show is due to go on for two-and-a-half hours and will be closed by a performance by soul legend Diana Ross.

The evening will also highlight global themes that have emerged or evolved during the Queen's reign including British and Commonwealth contributions in the fields of fashion, sport, the environment and pop music.

What else is happening?

Meanwhile, the Earl and Countess of Wessex have visited Northern Ireland to celebrate the Jubilee,

They first visited Belfast, where the Royal couple joined members of the public at a 1950s-themed celebration on Royal Avenue in the city, before meeting groups of performers.

They also listened to people sharing their memories of the monarch, joined in with craft activities and tried a local delicacy called the Belfast Bap.

The royal couple then headed to Bangor to join members of the public at a vintage funfair, where the Countess took part in a dance demonstration and the Earl tried his hand at pulling a pint of Guinness.

On Sunday, around 10,000 people are due to parade through the streets around Buckingham Palace for the Platinum Jubilee Pageant,

Hundreds of millions around the world are expected to watch the extravaganza on TV, and tens of thousands in person, as it winds its way around a 3km route.

Procession highlights are set to include a six-metre tall version of the Queen's wedding cake, a bus-sized dragon, puppet corgis, and an aerial artist suspended under a helium balloon.