It may be wishful thinking on the part of the gossip industry that Kate Middleton has asked sister Pippa and brother-in-law Harry to organize her a “wild” 30th birthday party, as the British magazine Grazia reported this week. Palace spokespeople have naturally denied those rumors, insisting that any celebrations will be “quiet and private.”

No matter how Catherine, Duchess of Cambridge—as we must try to learn to call her—will be toasting the most remarkable year of her life, one thing is certain: she’s about as likely to allow herself to be photographed falling out of a nightclub with Prince Harry as the queen is to host a karaoke night at Buckingham Palace.

For if there is one thing Kate has shown in the past year, it is that she is not the kind of girl to make an unforced error like that. From the moment she clambered aboard her father-in-law’s car for a crowd-pleasing drive around Buckingham Palace after the wedding, she has proved to be a consummate master of the common touch. Her amazing performance for the record crowds outside Sandringham Church on Christmas Day have led to comparisons with Diana, but in fact those are wide off the mark.

As Kate enters her 31st year, it’s quite apparent that she isn’t Diana 2.0. Princess Di was naïve, where Kate is savvy. In a way that Diana never saw until it was far too late, the Duchess of Cambridge understands the perils of her position: the politics, the power plays, and how things could turn very nasty, very quickly were she to become identified with the idle rich at a time of austerity in the UK.

But just because Kate is now the queen in waiting that doesn’t mean she is about to abandon her own personality. Nor will she dismiss the middle-class, “normal” values that made her such a catch for William, and continue to make her so popular around the globe.

The best part about the Public Kate is that it’s actually not an act. People who have met and worked with the royals all say the same thing: William and Kate really are just like they seem—down-to-earth and alarmingly normal. When they are in Anglesey, they stay in and watch telly at night. (Downton Abbey is a favorite.) They have the lightest staff of any of the senior royals. When a housekeeper was hired for Kate without her knowledge, Kate promptly reversed the hiring. Why would she want a housekeeper? she asked. To cook and shop and clean up after her and her husband, she was told. Kate replied that they were perfectly capable of doing their own cooking, as well as loading the dishwasher and going to the supermarket themselves (even if she does have to take a bodyguard along for the ride).

When the time comes, Kate may well be the first royal mother to do without a nanny, which would be an extraordinary and hugely symbolic nonhire.

She has made no secret of the fact that she is determined to lead as normal a life as possible for as long as possible. For example, the royal couple often travel up and down to Wales from London on the regular train. They travel first class, with their protection officers of course, but other people are allowed in the carriage and they get a drink from the buffet car like everyone else. There is certainly no question of a carriage being cordoned off or of the royal train being requisitioned every time they want to make the trip.

And yet, at the same time, Catherine is effortlessly dignified and elegant, encapsulating everything that a modern royal princess should be—even if she is “only” a duchess. She has clearly been helped by the fact that over the past year she has appeared incapable of taking a bad photo. Whether it’s at big, formal events or visiting charity establishments, Kate always judges the mood perfectly.

Kate knows, probably better than anyone else on this planet, the power of an image. The idea that she would jeopardize everything she has achieved this year by allowing herself to be photographed singing karaoke in leg warmers with Harry and Pippa is too absurd to contemplate.