PITY the poor celebrity.

There were a few moments, mid-Leveson Inquiry, when at least some people in this country felt a flicker of empathy for the stars. At one point, Hugh Grant was relating how a paparazzo drove a car at high speed towards his child's grandmother, while at another Sienna Miller was describing the ordeal of having her phone hacked.

The moments didn't last long but reinforced the notion of the star as victim. It is one that has surfaced again over the past week, as the saga of the topless pictures of the Duchess of Cambridge has unfurled. But is this really what we believe? It seems to me that a much stronger moral notion exists at the beating heart of our culture. It is the belief that, when stars begin to court fame, when they package their lives through press releases and orchestrated interviews during which they divulge their passions and involve us in their personal story, they sign a Faustian pact. It may not be written in black and white, but effectively says: "You can have our attention, money, adulation, but you can't keep even some little piece for yourself – you have to give all. And if what you present is a lie, or inauthentic, we will expose you as a fraud or hypocrite."

Auberon Waugh once wrote that it was "one of the oldest pastimes of the poor and unprivileged to gossip about the rich and powerful". Being the subject of such gossip was, he argued, "a small price to pay for being rich, or beautiful, or exceptionally talented, or even famous". He added that "if, as a famous person, you are in the habit of doing things which would make you ashamed if they were more widely known, then you have a clear choice between changing your habits, changing your attitude to them or retreating from the public stage".

One could say that the Duchess of Cambridge knew what she was letting herself in for. With the parable of Diana laid baldly before her, she can only have been aware of the pact she too was making. She knew the media context she was entering, and, no doubt, that it was her job to charm us, to become our new Princess of Hearts. The woman who married Prince William had to know the world would take every little bit of her.

And are we so sure she finds these photos, as has been quoted, "grotesque"? Isn't it possible that she doesn't mind them so very much and this is only the political spin of St James's Palace? And wouldn't it have been better if they had let the whole thing blow over, as they did with those naked Harry pictures, making the assumption that no-one really cares whether our future Queen gets her boobs out while sunbathing or not?

Indeed, in some ways, these topless photos are a non-event, so much part of the pattern of photography of female celebrity that it seems an absurd reverence that there was any attempt to shield the duchess from their publication. Whenever we see a glamorous, beautiful woman, with a culturally ideal body shape, flawless skin and great wardrobe, there will always be the cellulite shot, the topless snap, the invasion of bodily privacy that show us that, really, these flawless individuals are just like the rest of us.

Indeed, in some ways, this picture genre tells exactly the same story of how we feel about celebrities as the one about Hugh Grant and Divine Brown, or Tiger Woods's affair. They are an expression of the fact that we are uncomfortable with the airbrushing, the perfect picture of a life, even though so often we buy into it. In the end, we want to know that these stories aren't real, that Kate is not the model of modesty and good behaviour, but a woman who does that very banal thing of taking off her bikini top in the sun.

This is also how we feel about most celebrities. Our bitterness about the minor deceptions of a few beautiful people who provoke our fantasies and sing the money out of our purses is, I believe, really a feature of an age of anxiety about spin and honesty. Indeed, all this fuss about privacy is just a small backlash against the greater movement towards transparency, which is what people want, what they desire in their workplaces, demand of their politicians and doctors, and want of their celebrities.

So when we see female stars lending their faces to cosmetics commercials, or posing for perfect Hello wedding shots, our authenticity radars start bleeping. There are far greater and more sinister deceptions. But we don't like dishonesty, however small, and if it is connected to the very human stories of our modern-day gods, they are all the more likely to get us emotionally fired up.

This "right to privacy" is, for the most part, something that belongs to the famous. It is an aspect of their privilege. We know this – and this is why we struggle to feel sympathy.

We also know most celebrities have chosen this. When they complain about the invasion of their privacy, yet still cling to their fame and public profile, I think of Waugh's suggestion that they retreat from public life. They could at least try to duck out, and some do. But many stay. And what does that tell us? That this Faustian pact has got to be a good one: clearly, it is well worth signing up to.