Why does anyone dream about being a princess? Traditionally, they make the dullest of movie heroines: skipping around being sweet and innocent, falling victim to wicked stepmothers, waiting to be transformed by the magnificent attention of a handsome prince.
In a sensible world, little girls would have birthday parties where they dress up as active, gutsy female role models – say, Ripley from Alien. What seven-year-old worth her salt wouldn't delight in seeing an alien pop out of a chest-shaped cake? By and large, though, they don't get the option. From the moment they can focus on a screen, wall-to-wall princesses are sold hard to them by entertainment giant Disney, whose all-American values clearly do not extend to republicanism.
This year will see two biopics of real princesses, aimed at a market that would, at the very least, appear to be grownup. In September, Naomi Watts will star as the late Princess of Wales in Diana. At the end of the year – just in time to qualify for next year's Oscars – Nicole Kidman will star as Grace Kelly in Grace of Monaco. Fans of films in which Australian actors play iconic blond princesses who died as a result of car accidents are set for a double bill. Meanwhile, for those who would rather watch the real thing, Grace Kelly herself will be on cinema screens around the country from next week in a re-release of Alfred Hitchcock's 1954 mystery Dial M for Murder. Originally filmed in Natural Vision stereoscopic 3D, the film has now been converted to digital 3D.
Grace of Monaco and Diana may be different takes on princess genre, which has been quietly evolving in recent years. Gradually, Disney princesses shifted from marshalling woodland creatures into domestic servitude to reading books and acting feisty. Lately they have upped their game, turning to archery (Brave), entrepreneurship (The Princess and the Frog) and defeating Hun warlords (Mulan). There are goth princesses (Snow White and the Huntsman), ogre princesses (Shrek), and Disney princesses who spoof other Disney princesses (Enchanted). Why not real princesses?
Yet the experience of many real princesses seems to have been less like a Disney fairytale, and closer to the sinister versions found in complete editions of Hans Christian Andersen or the Brothers Grimm. Reportedly, Grace of Monaco revolves around a "crisis" in her marriage to Prince Rainier III in the early 1960s. At that time, Monaco was in trouble with France over its tax policies, and public outcry prevented Grace from taking up the starring role in Hitchcock's Marnie. The role went to Tippi Hedren; Grace never appeared onscreen again. By the time she was in her 40s and living largely apart from her husband, her fantasies were no longer about being a princess. She told friends that she dreamed of becoming a bag lady and wandering the streets of Paris.
Diana, meanwhile, is set during the last two years of Princess Diana's life. The real Diana is venerated as a saint in some quarters of the British press, who are doubtless waiting to see if the film is nice about her (in which case they will like it) or nasty (in which case they won't). The minute-long teaser trailer touches on familiar points: fame, landmines, hunky heart surgeon, big shiny yacht, intrusive paparazzi. The director, Oliver Hirschbiegel, is best known for Downfall, which recounts the last days of a rather different historical figure: Adolf Hitler.
The British royals have not commented on the Diana movie, but the Monégasque royal family – now headed by Albert II, Rainier and Grace's son – have weighed in on the Grace one. A statement claimed the film "contains important historical inaccuracies as well as scenes of pure fiction" and has been "pointlessly glamorised".
Since the whole purpose of princesses is to disburse glamour (especially when that word is imbued with its old meaning of magic or enchantment), one wonders what happens if glamorising them becomes pointless. The family's objection is a reminder, though, of how completely royals are obliged to surrender their privacy. Monarchy, wrote Hilaire Belloc in 1938, "imperils the soul of the Monarch … His individual being, the man himself, ceases to be."
The private lives of royals have always been public property, including their most intimate functions. Long before they were photographed playing strip-billiards, royals were required to give birth in front of crowds of spectators, or defecate with the assistance of a lucky member of the gentry who was designated Groom of the Stool. For some reason, these details have not yet ended up in a Disney princess movie.
It will be interesting to see what Grace of Monaco and Diana make of their real princess subjects. A major rewrite would have to be done on either life to make it a great advert for marrying a prince, handsome or otherwise. Their stories are about being careful what you wish for: the not-so-glittering reality behind once upon a dream. Perhaps, having had princess fantasies rammed down their throats from childhood, some women will find it reassuring – even gratifying – to see that "happily ever after" has been substantially oversold. Anyone for a slice of Alien cake?
• Dial M for Murder is re-released in the UK on 26 July, Diana is released on 20 September and Grace of Monaco on 10 January 2014.
guardian.co.uk © Guardian News and Media Limited 2010