Royals rarely show public displays of affection, but Kate Middleton disregarded protocol Sunday with a subtle, yet sweet gesture toward her husband, Prince William.
The Princess of Wales gave Prince William a quick pat on his behind as they walked the red carpet at the British Academy of Film and Television Arts awards, a move that "seemed really natural" for the couple, one expert says.
Human behavior expert Susan Constantine told Fox News Digital Kate and William looked "extremely happy" at the ceremony in London.
"I think it's who they are behind closed doors," Constantine said. "I'm kind of glad to see them kind of opening up and being a little freer and showing that kind of affection."
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Vogue initially shared a short clip of the "love tap" on Instagram and wrote the "royals really are just like us — a regular husband and wife that sometimes like to cop a feel."
"I think what happened is that the two of them — behind the cameras and by themselves — this is what they do all the time," Constantine said. "I think she got caught up in the moment, and it was just an instantaneous reaction to pat him on the rear.
"There wasn't any sort of performance. They weren't doing it to play up to the audience. They really were having a moment between the two of them. And, yes, there was lots of stuff that was going on around it, but they were so comfortable in that environment, and it didn't prohibit the intimacy that the two of them had.
"That's a good thing, because I see things differently with Harry and his wife," she noted. "There's a lot of performance stuff going on there. In this case, I think it's just the two of them, who they are and authentically loving each other, feeling free and open about showing affection, which is what they've been prohibited from doing."
Kensington Palace did not immediately respond to Fox News Digital's request for comment.
"Kate and William do look much less inhibited with their PDAs now that they have moved up the royal pecking order," body language expert Judi James told The Sun. "The bottom pat from Kate also showed where some of the power behind the scenes might lie."
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James also agreed that the couple "looked totally relaxed" on the red carpet. "They used more eye contact than usual, and their touch rituals had increased to create a suggestion of flirting," she said.
"William and Kate's tactile, playful behaviors could be an answer to Harry with his comments about coolness and royal men marrying women who ‘fit into the mold.’ This seems to be Kate showing she should not be fitted into any mold, with her Hollywood-style glamour and her very cheeky gesture to her husband."
Lip reader Sophia Martell told the Daily Mail the Princess of Wales was simply recreating something she had seen in the crowd moments before.
Martell claimed Kate told William, "That man, he tapped her on the bottom." William was intrigued with what his wife said and seemed to lean to ask, "Did he?"
Middleton then reenacted the moment by tapping William on his behind. She then appeared to proclaim, "That was so funny."
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Middleton sported a floor-length, one-shouldered white gown by late British fashion designer Alexander McQueen, a dress she previously wore to the 2019 awards show but styled slightly differently
She's a longtime fan of the designer, who created with Gucci and Givenchy and was once named the commander of the British Empire for his leadership in fashion.
Kate styled the dress with dramatic black opera gloves and gold Jimmy Choo pumps to match a pair of ornate Zara earrings.
She carried a black silver clutch with matching gold statements in her hand while walking alongside her husband, who serves as the president of the film and television academy.
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Their attendance Sunday marked their first BAFTAs appearance in two years and their debut as the Prince and Princess of Wales following Queen Elizabeth II's death in September.
The couple missed the 2021 ceremony due to the death of his grandfather, Prince Philip, who died the morning before the BAFTAs. Scheduling constraints prohibited the pair from attending the 2022 show.