As the festivities surrounding King Charles III and Queen Camilla's coronation continued this weekend, his eldest grandchildren were front and center to join in the fun.

Prince George, 9, and Princess Charlotte, 8, joined their grandfather, his wife and their parents Kate Middleton and Prince William on the grounds of Windsor Castle May 7 to watch the official Coronation Concert. Performers included Katy Perry and her American Idol co-judge Lionel Richie, as well as British pop group Take That and singer Andrea Bocelli.

For the coronation concert, Charlotte wore an ivory chiffon Self Portrait dress with a scalloped collar. George wore a dark suit, as did his dad, while Kate sported a red Alexander McQueen pantsuit. The Wales family stood beside Charles and Camilla, who cheered and waved at the crowd.

Not spotted: the Prince and Princess of Wales' youngest son, Prince Louis, 5, who had joined the royal family at the coronation ceremony at Westminster Abbey a day earlier. (See every must-see moment from the event.)

Also missing at the concert: Charles' younger son Prince Harry, who left the coronation ceremony just after it ended to catch a flight back from London to California to be with his wife Meghan Markle and their kids, Princess Lilibet, 23 months, and Prince Archie, who celebrated his fourth birthday the same day.

Hours before the concert, Kate and William surprised fans with a walkabout at Windsor. Kate wore a pastel blue blazer over a white top and black pants, paired with white sneakers, while her husband sported a navy suit with no tie. The couple visited a street fair, where they took selfies with members of the public and sampled homemade gin.

See photos of the royal family at the Coronation Concert and Kate and William on their impromptu walkabout below:

Kate Middleton and Prince William arrive at King Charles III's Coronation Concert at Windsor Castle with their two eldest children, Prince George and Princess Charlotte on May 6, 2023.

Kate Middleton appears with her and Prince William's eldest kids, Prince George and Princess Charlotte, with William's cousin Princess Eugenie standing behind them at King Charles III's Coronation Concert.

King Charles III appears with his heir Prince William and eldest grandson Prince George.

King Charles III and his wife Queen Camilla wave at the Coronation Concert at Windsor Castle May 7, a day after they were crowned.

Kate Middleton and Prince William's eldest kids enjoy the show.

Kate Middleton appears at the concert with Princess Charlotte.

Kate Middleton and Prince William's daughter waves a flag.

The singer takes the stage.

The singer performs onstage.

The Downton Abbey actor addresses the stage.

The singer performs onstage.

The musician performs at the concert.

The singer performs onstage.

The singer appears at the concert.

The pianist performs onstage.

Prince William greets fans during an impromptu walkabout at Windsor May 7, a day after his father King Charles III's coronation and hours before the Coronation Concert on the castle's grounds.

Kate Middleton takes a selfie with a fan during a surprise public appearance at Windsor May 7, a day after King Charles III's coronation.

Kate Middleton is all smiles during her and Prince William's surprise post-coronation walkabout at Windsor May 7.

Prince William and Kate Middleton are offered drinks at a street fair at Windsor as they make a surprise public appearance a day after his father King Charles III's coronation.

For the latest breaking news updates, click here to download the E! News App