The couple have shown affection towards their children in public ever since Prince George was born in 2013.
Kate and William will often be seen holding the children’s hands or picking them up for a cuddle.
Previously, affection towards children would have been frowned upon within the Royal Family.
According to one expert, protocol within the family could be “evolving” and “softening”.
Speaking to Express.co.uk, Danielle Haig, Principal Psychologist from DH Consulting, said: “The overt affection that William and Kate show towards their children is most definitely unusual for the British Royal Family.
“But my, how wonderful it is to see.
“As a psychologist, it is well known that children need to feel affection, love and safety from their parents to truly thrive and be happy in life.
“To be kept at an arm’s length and not shown affection as a child, can have all sorts of negative impacts on a child psychologically and emotionally.”
Danielle explained that it is “healthy” to be affectionate as a family, especially one in the public eye.
She added: “I’m glad that Kate and William feel comfortable enough to display this playfulness with their children to the world.
“It seems that protocol in the Royal Family is softening and evolving with the times.
“With the amount of influence that the royal couple have, our future King and Queen are setting a great example to other parents to unapologetically enjoy their time with their children.
“I feel like they are showing the world that they are just like us and they are progressing the behaviours and attitudes of Princess Diana in their openness with their parental affections.”
The last time Prince George was seen in public was to watch the UEFA Final 2020 with both of his parents.
Sitting in the middle of Kate and William, body language expert Judi James told Express.co.uk that the couple approached George in ways to help boost his “confidence”.
She said: “Kate and William tended to approach their son rather than the other way around and again this will help increase his feelings of importance and confidence.”
Other Royal Family members including Sophie, Countess of Wessex and Prince Edward have also used the parenting technique of bending down to eye-level when speaking to their children.
According to Leon Hady of Guide Education, this is done so to “built trust”.
He said: “Being close, at eye level, speaking with a reassuring tone creates a feeling of understanding and closeness that assures a child and makes them feel connected better to the parent.
“Very good, supportive practice.”
Source: EXPRESS CO UK