While the royals occasionally let their guards down and share rare affectionate moments in public, on the whole they're professional and formal when out and about on official duties.
Prince Charles is rarely seen touching his wife Camilla, and the Cambridges have strict 'on-duty' behaviour.
But when Prince William tried a rare PDA during the couple's appearance on Mary Berry's A Berry Royal Christmas back in 2019 - it was well and truly shot down.
In fact, some viewers described the moment as extremely awkward and said Kate "recoiled" from her husband's touch - however others praised her for trying to keep things professional and trying to avoid stealing the show.
The moment occurred as the couple sat down to speak to charity volunteers at a Christmas party, which was being catered by former Great British Bake Off judge Mary.
Twitter users picked up on Kate's reaction to William's touch.
One wrote: "Awkward! Too awkward!! They should have cut it out."
Another said Kate 'moved with a quickness' after her husband reached out for her.
A third person commented: "Kate shaking off William's hand on her shoulder during #ABerryRoyalChristmas."
One royal watcher said she reacts the same way when her mum touches her shoulder because it makes her feel uncomfortable.
However, others insisted people had misinterpreted the behaviour.
One fan tweeted: "LOOK WHAT ACTUALLY HAPPENED. Kate is beautifully content as William’s hand rests on her shoulder. FIRST William STARTS to remove his hand, AFTER Kate simply shifts."
Another person commented: "I like the way they interact, it’s professional. I don’t want to see excessive hand holding and back rubbing. It’s awkward, like you’re intruding on a private moment."
Another said: "I think he tickled her back or shoulder. She did move but there were no dirty looks or even a facial reaction."
Over the years Kate and William have shared some PDAs, which always delight fans.
Their engagement and 10th anniversary official photos show them cuddling tightly together and looking lovingly into each others eyes.
Behind-the-scenes photos from William's Earthshot Prize Ceremony show Kate placing her hand on her husband's back, and she had her hand on his knee in their 2020 Christmas card.
When Meghan Markle joined the family, Prince Harry raised some eyebrows by taking a much less formal approach to joint engagements. They loved-up couple held hands throughout their outings and couldn't keep their hands off each other.
But the majority of people loved the intimacy of it, describing it as a refreshing approach to royal life and sharing their happiness.
