It's a royal surprise!
Kate Middleton and Prince William headed to Cardiff Castle in Wales as part of the festivities for Queen Elizabeth II's Platinum Jubilee and brought along two special guests—Prince George, 8, and Princess Charlotte, 7, the eldest of their three children.
The family all greeted well-wishers who lined up to see them, including performers and crew members involved in the special Platinum Jubilee Celebration Concert taking place in the castle grounds that day. During their trip, the Duke and Duchess of Cambridge and their kids checked out the show's music setup backstage.
Charlotte wore a navy wool coat dress and Mary Janes, while George and William sported navy suits and Kate was dressed in a red wool coat dress and black stiletto pumps.
"Cardiff, it's been wonderful to join you this #PlatinumJubilee weekend!" Kate and William wrote on Instagram. "So lovely to meet the stars and team behind tonight's concert at Cardiff Castle. We had an extra special drum demonstration for George and Charlotte, saw a stunning performance from the Wales Youth Choir for Good and had a sneak peak at how today's show will come together! Have a great time at the concert this evening!"
The family's visit to Cardiff Castle comes two days after all the Cambridges, including youngest son Prince Louis, 4, joined the Queen and other royals on a Buckingham Palace balcony to watch the Trooping the Colour parade.
The annual event is the official birthday celebration for the ceremonial monarch, who turned 96 in April, and kicked off four days of festivities for the Platinum Jubilee, which marks her 70th year on the throne.
Also spotted at Trooping the Color parade, William's brother Prince Harry and wife Meghan Markle, who did not watch from the balcony, which was reserved for senior royals. The couple left their royal positions two years ago.
See photos of the Cambridges during their visit to Cardiff Castle: