The Queen and the Prince of Wales have joined thousands of people for the second day of Royal Ascot.
Pictures from the event showed Prince William wearing a top hat and morning dress as he arrived at the races in a horse-drawn carriage.
The event, one of the highlights of the summer social calendar, is taking place over five days at the Berkshire racecourse and is expected to draw more than 250,000 spectators from around the world.
Arriving in the same carriage as Prince William were Queen Camilla and the Earl and Countess of Halifax.
The King, who is being treated for cancer, attended Ascot for the opening day on Tuesday, but was not at the event on Wednesday.
Michael and Carole Middleton, the parents of the Princess of Wales, joined members of the Royal Family.
On Saturday, the princess made her first public appearance since she was diagnosed with cancer, attending Trooping the Colour to mark the King's official birthday.
Ahead of the parade, the princess released a statement saying she had been "blown away" by the messages of support she had received since her diagnosis in March and had been "making good progress" but was "not out of the woods yet".
"As anyone going through chemotherapy will know, there are good days and bad days. I am learning how to be patient, especially with uncertainty.
"Taking each day as it comes, listening to my body, and allowing myself to take this much needed time to heal."
She added she was hoping to join a few public engagements over the summer.
The Middletons' attendance at Ascot is also believed to be their first public appearance since their daughter began treatment.
In other carriages were Prince Andrew's daughter Princess Eugenie with her husband Jack Brooksbank and composer Andrew Lloyd Webber, who on Monday was made a Knight Companion of the Order of the Garter at a ceremony attended by the King and Queen.
Also at the event were the Princess Royal's daughter Zara Tindall, herself an accomplished equestrian, and the Duke of Edinburgh.
Prince William later handed out prizes to the winners of the annual Prince of Wales's Stakes race.