As the Wales vs. England Six Nations rugby match unfolded last night, Princess Kate and Prince William also offered a glimpse into their fun-filled relationship. Even while supporting opposing teams they were engaged in a subtle, playful chatter of their own. Body language expert Judi James has analysed their behaviour, revealing the cheeky banter that went on during the game. The pair were at the match at the Principality Stadium in Cardiff, with their patronages seeing them back opposing sides. While Prince William has been patron of the Welsh Rugby Union (WRU) since 2016, Kate has been patron of Rugby Football League (RFL) since 2022 after taking over from Prince Harry. While all eyes were on the match, William and Kate's body language didn't go unnoticed. According to Judi, William's playful expression was evident right from the start. "It's William's facial expressions of mischievous, playful fun that suggest the banter that's going on between them here," she told The Mirror. "At the start of the game, we saw Kate sitting looking serious and even slightly tense, but William was beaming smugly as though assuming his side would win, show-boating a little as he shook hands and chatted with people around him and waved, beaming, to other fans." According to the pro, William appeared to take the lead in terms of confidence, standing with a smug smile, shaking hands, and waving to fans. His upbeat attitude suggested he was already assuming his team's victory. Meanwhile, Judi says that Kate seemed a little more serious, her face reflecting a hint of tension as she focused on the match. As they took their seats in the stadium, the Princess of Wales could be seen sitting next to Rob Udwin, president of the RFU, and the pair appeared to share a "nervous" whisper. Turning to him, Kate said: "He is nervous, I can see he is", a lip reader told the Mirror. Whilst it's unclear which player they were discussing, in response, Rob said: "He is certainly not an amateur" leading Kate to agree, "he certainly is not". Rob then said: "He is very impressive", with Kate nodding in agreement, saying: "He plays very well as I imagined". However, the tension eased as England began to pull ahead and Kate's more playful side emerged. According to Judi, she flashed a 'naughty' dimpled smile, showing her enjoyment of the friendly rivalry, much to the amusement of William. The body language expert said: "As the scores stacked up in England's favour it was Kate performing a 'naughty' dimpled smile, while William stuck to his puckered-mouth grins to suggest he was still enjoying the banter." The couple, who are famously competitive, have previously joked about supporting different teams during the tournament, with William supporting Wales and Kate rooting for England.