When it comes to public displays of affection, Kate Middleton and Prince William sometimes… hold hands? And even that’s viewed a huge deal, which all comes down to PDA not exactly being in the royal protocol rule book. But apparently the vibes are verrrrry different when cameras shut off.

Veteran royal reporter Katie Nicholl tells The Mirror, “I’ve been with them on many occasions, and when the cameras drop, you’ll often see them walk away and Kate will put an arm around his waist, or he’ll place his hand in the small of her back.” She adds, “There’s a lovely closeness between them, and whereas at the start of their marriage they seemed shy about being affectionate in public, they’re so much more confident now.”

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That said, apparently William and Kate’s marriage isn’t 100 percent smooth sailing. Per Katie, “They’ve been together for nearly a quarter of a century. Of course there are going to be hiccups.”

Of course, said hiccups remain largely out of the public eye, and now the couple are gearing up for their 15-year wedding anniversary next April. Katie says that while “they tend to do things in a low-key way, but it wouldn’t surprise me to see them do something special to recognise 15 years of marriage next year.”

Adorable!