Prince George and Princess Charlotte Join Kate and William for Surprise Visit to Wales for Platinum Jubilee!

Prince George and Princess Charlotte Join Kate and William for Surprise Visit to Wales for Platinum Jubilee!

Prince George and Princess Charlotte were a surprise addition on Kate Middleton and Prince William's outing to Wales on Saturday.

Kicking off the third day of the Platinum Jubilee celebrations, the Cambridge family (minus 4-year-old Prince Louis, who was likely deemed too young for the visit!), visited Cardiff Castle to take in the local celebrations being held in honor of Queen Elizabeth.

The day is especially poignant for 8-year-old George, whose visit mirrors his father's first official trip to Wales when he was the same age. Back in March 1991, he joined his mother Princess Diana and father Prince Charles in Cardiff. The excited crowds handed the young prince daffodils — the Welsh national flower — as he went on a walkabout outside Llandaff Cathedral.

Their appearance in Wales underlines one of the main objects of the Jubilee weekend — to not only celebrate the Queen's 70-year reign, but to also stress the future and the succession of the monarchy. In George and William, we have two future kings and two future Princes of Wales.

RELATED: Prince George, Princess Charlotte and Prince Louis Make Their Carriage Debut at Trooping the Colour!

The Duke and Duchess of Cambridge, Prince George and Princess Charlotte during their visit to Cardiff Castle
The Duke and Duchess of Cambridge, Prince George and Princess Charlotte during their visit to Cardiff Castle

PA Images / Alamy Stock Photo Kate Middleton, Prince William, Prince George and Princess Charlotte

"The Jubilee is of historic significance but it's equally an opportunity to show the succession and the monarchy as a whole," a royal source tells PEOPLE.

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The children, who held hands with their parents, are meeting performers, including singer Bonnie Tyler (who was honored by the Queen in her annual birthday awards), and crew involved in a special Platinum Jubilee Celebration Concert taking place on the grounds of Cardiff Castle.

WALES, ENGLAND - 01/03/91 M010176 CARDIFF, WALES PRINCESS DIANA , PRINCE CHARLES & PRINCE WILLIAM.A©1991
WALES, ENGLAND - 01/03/91 M010176 CARDIFF, WALES PRINCESS DIANA , PRINCE CHARLES & PRINCE WILLIAM.A©1991

Globe Photos/ZUMAPRESS.com Princess Diana, Prince William and Prince Charles during a visit to Cardiff in 1991

Kate wore her Eponine red coat dress with her DeMellier bag and Spells of Love gold earrings (the designer is Welsh!) and Charlotte stepped out in her go-to Amaia coat in navy.

At one point, the royals joined the orchestra on stage as they played Welsh singer Tom Jones' hit "Delilah." They moved along the stage to then watch a rock drummer do a roll. The live music entertainment will be especially fun for George. Kate previously revealed that the young prince is learning to play the guitar.

Prince William, Catherine Duchess of Cambridge, Prince George and Princess Charlotte Duke and Duchess of Cambridge will visit Cardiff Castle
Prince William, Catherine Duchess of Cambridge, Prince George and Princess Charlotte Duke and Duchess of Cambridge will visit Cardiff Castle

Tim Rooke/Shutterstock Kate Middleton, Prince William, Prince George and Princess Charlotte

The family — with Charlotte, 7, clutching her dad William's hand — then went to watch dancers and young musical performers on the castle lawns.

As Bonnie Tyler warmed up with "Total Eclipse of the Heart," they chatted with to some of the food stall vendors preparing for the concert crowd. The family then delighted a small crowd of locals who had been allowed inside the castle before the gates closed.

Catherine, Duchess of Cambridge and Princess Charlotte of Cambridge depart from Cardiff Castle
Catherine, Duchess of Cambridge and Princess Charlotte of Cambridge depart from Cardiff Castle

Samir Hussein/WireImage Kate Middleton and Princess Charlotte

William, who had his arm across his son's shoulder, encouraged George to shake some hands as the excited well-wishers chatted to them. Charlotte was also ushered in to join in the chat.

Prince William shared a special moment with Siobhan Lewis, 37, who has cerebral palsy, and her mother Tracey, from Cardiff. Siobhan told the prince that she met Princess Diana when she was at the Peto Institute in Budapest, Hungary.

"He was happy to hear that and said that he knew she'd been to Hungury a few times," Tracey tells PEOPLE.

The Duke and Duchess of Cambridge, Prince George and Princess Charlotte speak to wellwishers during their visit to Cardiff Castle
The Duke and Duchess of Cambridge, Prince George and Princess Charlotte speak to wellwishers during their visit to Cardiff Castle

Ben Birchall/PA Images via Getty Images Kate Middleton, Princess Charlotte, Prince George and Prince William

All the royals gathered around to chat with her, and Kate was drawn to the bright buckles on her red sneakers.

"Catherine really loved the sparkles on my shoes," says Siobhan. "I gave her a bouquet of flowers. They were sweet Williams. William said, 'How sweet.'"

"We both shook all their hands. We knew William and Kate were coming but it was an added bonus having the children. It was really lovely. They were all wonderfully relaxed and friendly," she says.

The Duke and Duchess of Cambridge, Prince George and Princess Charlotte speak to wellwishers during their visit to Cardiff Castle
The Duke and Duchess of Cambridge, Prince George and Princess Charlotte speak to wellwishers during their visit to Cardiff Castle

Ben Birchall/PA Images via Getty Images Prince George, Prince William, Princess Charlotte and Kate Middleton

The family also chatted with a group of local Scouts.

"George and Charlotte asked how I got my badges," Jack Lovatt, 12, tells PEOPLE. "And William asked George if he had done similar in scouts."

Catherine, Duchess of Cambridge, Princess Charlotte of Cambridge, Prince George of Cambridge and Prince William, Duke of Cambridge depart after a visit of Cardiff Castle
Catherine, Duchess of Cambridge, Princess Charlotte of Cambridge, Prince George of Cambridge and Prince William, Duke of Cambridge depart after a visit of Cardiff Castle

Samir Hussein/WireImage Kate Middleton, Princess Charlotte, Prince George and Prince William

A fun moment for George and Charlotte came when they were introduced to a goat named Shenkin the Fourth — the mascot of of the 3rd battalion Royal Welsh regiment.

"They were very excited to meet him," handler Sgt. Mark Jackson tells PEOPLE. "So when I explained that he also helps escort the Welsh rugby team out at the Principality Stadium, Prince George was even more excited by that. Both the children were mesmerized by Shenkin."

Shenkin and Sgt. Jackson were among the battalion's band, which was providing a festive musical backdrop as the royals left.

"It was a beautiful surprise for Cardiff to have the children here and an absolute privilege and honor for us to be here and meet the royals and welcome them to Wales," he adds.

Prince William, Duke of Cambridge, Britain's Catherine, Duchess of Cambridge, and their children Britain's Prince George and Britain's Princess Charlotte check a concert's music setup backstage
Prince William, Duke of Cambridge, Britain's Catherine, Duchess of Cambridge, and their children Britain's Prince George and Britain's Princess Charlotte check a concert's music setup backstage

ASHLEY CROWDEN/AFP via Getty Images

The Cardiff event is hosted by presenter Aled Jones and Shan Cothi, and will feature live performances from some of Wales' best-known singers and entertainers, alongside choirs, bands and orchestras. And the performances will finish at 7 p.m U.K.-time, allowing the audience to then watch the Platinum Party at the Palace on big screens set up on the grounds of the castle.

Prince George of Cambridge and Princess Charlotte of Cambridge hold gifts of flowers during a visit to Cardiff Castle
Prince George of Cambridge and Princess Charlotte of Cambridge hold gifts of flowers during a visit to Cardiff Castle

Chris Jackson/Getty Images Prince George and Princess Charlotte

Later today, William and Kate will attend the concert held outside of Buckingham Palace, where William and his father Prince Charles will pay tribute to the Queen in speeches they are set to give on stage.

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The Duke and Duchess of Cambridge, Prince George and Princess Charlotte speak to wellwishers during their visit to Cardiff Castle
The Duke and Duchess of Cambridge, Prince George and Princess Charlotte speak to wellwishers during their visit to Cardiff Castle

Ben Birchall/PA Images via Getty Images Prince George and Princess Charlotte

The Queen will take in the festivities while at home at Windsor Castle, where she will be watching on TV.

William and Kate's visit to Wales is part of an effort by the royal family to spread out around the U.K. to thank people for their support during the Jubilee. Princess Anne and her husband Vice Admiral Sir Tim Laurence visited Scotland on Friday and Prince Edward and Sophie, Countess of Wessex are heading to Northern Ireland.