The Prince and Princess of Wales today shared a flirty moment in public as they joined King Charles and Queen Camilla for a day at the races.
Catherine was cheered by racegoers after she was spotted on the big screen taking part in the traditional royal carriage procession with Prince William.
She caught the eye of fashion fans wearing a red dress by Alexander McQueen and a matching Philip Treacy hat, while William looked smart in a morning suit and top hat.
Kate and William were pictured looking at the trophies on the penultimate day of Royal Ascot - and then greeted jockey Oisin Murphy after he won The Commonwealth Cup on Shaquille.
The Prince and Princess also shared a brief flirty moment, with Catherine giving William a cheeky tap on the bottom as they got ready to present a trophy.
Earlier this year, the Princess also gave William a pat on his bottom on the BAFTA red carpet and a clip of them went viral, with royal fans loving the cheeky moment and saying it was a flirty PDA.
According to body language expert Judi James, it seems the case that Kate performed the gesture following a mistake by William - and she used it as a reprimand.
She told the Mirror: "This bum-tap gesture is part of a swift series of non-verbal signals between the couple, known as tie-signs.
"They were clearly more tactile than usual for this red carpet appearance and their very glamorous styling gave them the look of an A-list power couple.
"Like all good A-listers, Kate seemed to be using tie signs or non-verbal cues to help choreograph their movements but there was one small moment when they appeared to fall out of sync, possibly due to the fact that William seemed unable to keep his eyes off his stunning wife."
Tonight, Kate celebrated and clapped from the royal box after the aptly named Sandringham Stakes was won by Coppice, ridden by popular jockey Frankie Dettori.
Other members of the Royal Family at the races today were Princess Beatrice, 34, and her husband Edoardo Mapelli Mozzi, 39, as well as Sophie, Duchess of Edinburgh, and Prince and Princess Michael of Kent.
Kate and William live close to the racecourse, having moved to their four-bedroom Adelaide Cottage in Windsor's Home Park last year, to offer their children more freedom away from central London.
They were spotted on Thursday with eldest son Prince George at William's former school Eton College, prompting speculation the young royal, who turns 10 next month, will follow in the footsteps of his father.
William and Kate were guests of the late Queen a number of times at Royal Ascot, a racecourse the monarch had a great affinity with and where she had more than 20 winners.
Charles and Camilla appeared ecstatic when their thoroughbred Desert Hero, an 18-1 longshot, won the King George V Stakes on Thursday - their first Royal Ascot win - and they have another chance of victory when Candle of Hope rides later in the Sandringham Stakes.
They were joined in the carriage procession by actress Dame Judi Dench, the Duchess of Edinburgh, and Princess Beatrice and her husband Edo Mapelli Mozzi.
When the King and Queen and their guests stepped down from the carriages in the parade ring, they mingled with trainers and jockeys ahead of the first race and popular rider Frankie Dettori walked over and chatted with William.
Dettori had a number of rides this week on horses owned by the King and Queen and failed to win but he put his racetrack frustrations behind him when he won the big race of the meet - the Gold Cup on Thursday.
After his chat with William, he won the first race of the day on Porta Fortuna and performed his trademark celebration jumping from his horse.
The prince and princess soon returned to the parade ring to present the trophy in the Commonwealth Cup won by Shaquille.
