She told the Express: “In the stills photos we can see two very strong ‘tells’ from William and Catherine to illustrate the strength of their amusement and good humour.”
The expert explained: “Catherine’s smile entails dimples plus a tongue that has appeared between her teeth to the side of her mouth, which hints at high levels of inner fun.
“William’s laugh here includes edge-to-edge teeth, which also signals how the couple are at the same level of playful enjoyment.”
She added: “William’s intense face-gazing behaviour as he looks at his wife shows just how finely-tuned they are to each other’s non-verbal signals and how strong his enjoyment is to be prompting what looks like a very carefree smile from her.”
The royal couple later dazzled at the glittering state banquet at Windsor Castle, where Catherine wore a new tiara.
In a nod to the King’s guests, the future queen diplomatically opted for Queen Victoria’s Oriental Circlet Tiara, made of diamonds and rubies, which was designed for Victoria by her German-born husband, Prince Albert, in 1853.