Duke and Duchess of Cambridge pack on the PDA during Ireland tour

The Duke and Duchess of Cambridge were more affectionate in Ireland. (Press Association)

The Duke and Duchess of Cambridge were surprisingly affectionate with one another during their three-day tour of Ireland.

The couple usually keep public displays of affection to a minimum, unlike the duke’s younger brother, who is regularly seen holding hands with his wife, the Duchess of Sussex.

On a walk along the Howth Head cliff, Catherine pulled her arm through her husband’s as he walked with his hand in his coat pocket.

In Galway, she lent in to whisper into the duke’s ear as the pair watched circus acts preparing for the celebrations for the European City of Culture.

And later, the duke gently placed a hand on the duchess as they left the crowds behind in a walkabout.

William reached out to touch Kate's arm during a walkabout. (Reuters)
The couple linked arms in Howth Cliff. (Press Association)

Body language expert Judi James told Yahoo News UK the pair have ramped up the public displays in a big way.

“Their PDAs have been slowly increasing recently and this cuddle is hugely out of character for them in public,” She says.

“It does seem linked to some of William’s increase in self-comfort rituals, like stomach-holding, hunching and adopting the fig-leaf pose with his hands.

“These traits suggest he is feeling under pressure, probably from the royal dramas and the split from his own brother. He is seen smiling and laughing in Ireland but his body language suggests some underlying vulnerability.

“Kate on the other hand looks more confident, engaged and outgoing in public. She is very much the active one in this double-act now and her rather watchful eye gaze suggests she is doing a lot to support William and to make him grin at every opportunity.

“The arm-linking on the walk was her gesture but the hugging did look mutual, suggesting increased levels of closeness behind the scenes as well as in front of the cameras.”

The duke and duchess posed for a picture at the top of the Howth Cliff. (Getty Images)

After the trip, they posted the moment at the top of their cliff on Instagram, as they thanked fans for the support they received in Ireland.

According to Town and Country Magazine, William also told one royal fan that he loves Kate.

Angela Moran from Westport, County Mayo, told the magazine: “I said to him that I really admired him and Catherine and he said thank you very much. I said I love her and he said ‘I do too, nice of you to say so.’”

Prince Harry and Meghan are well known for their public displays of affection, but the Cambridges tend to stick to stricter rules, not holding hands or embracing frequently.

William and Kate did return to their playful and competitive side in several of their engagements.

In County Meath, they played a few quick table tennis points, and then in Galway on their final day, they gave hurling a go, each eventually scoring a goal.