The Princess Diaries At 20: The Movie We Love To Love

An 'invisible' teen mouses about her business at her American high school. She has a sad, unrequited crush on the athletic jock. Her quirky best friend is always there to catch her when she falls. Their interests are decidedly uncool. A nerdy (but always very cute) classmate has a thing for her, but she just thinks of him as a friend. Then something happens – her life changes. Now she's cool, now she's attractive, now she's visible. The jock wants to be with her; so do all the coolest girls. She thinks her new friendships are real: she cruises for a bit, then stumbles. Her best friend is hurt, but eventually forgiving. The jock is a jerk (or just confused). The nerdy boy is the one for her, obviously. She learns her lesson about wanting a fake, flighty spotlight.

The plotline of the American high school movie is tried, tested, successful and clichéd. Every so often, there are attempts to reinvent it (most recently, in Never Have I Ever). We know exactly how it plays out – and that may be exactly why we love it. And have we ever loved it more than in The Princess Diaries, which turned 20 on July 29th? It may not have been as revolutionary as Mean Girls, as era-defining as Clueless or as delicately observed as Lady Bird. But Garry Marshall's sweet adaptation of Meg Cabot's novel (which apparently, as a friend assures me, outstrips the film by a mile) is perhaps the most feel-good and endearingly performed of them all.

It's hard to believe Anne Hathaway (as Mia) had never been in a film before: there's no awkwardness in her performance. She doesn't try too hard, but manages to balance physical comedy (the number of times she's required to fall off or into things!), genuine emotion and ordinary teen drama. A critic compared her to Julia Roberts – and with her wide-mouthed smile and open-faced charm, it's a pretty accurate comparison. Hathaway was, in a way, inheriting Roberts's mantle as the confused, slightly out-of-place heroine of a Garry Marshall movie. Roberts did it winningly a decade before in Pretty Woman – and there, too, the heroine was guided by the calm, affectionate and steadying presence of Héctor Elizondo. In The Princess Diaries, Elizondo plays Joe (not Joey), who is really Mia's grandmother's head of security, but moonlights as Mia's chauffeur, support system and fount of wisdom. He quotes Eleanor Roosevelt to her: 'Nobody can make you feel inferior without your consent.'

Mia's grandmother, Queen Clarisse Renaldi, is played by Julie Andrews in a sparkling late-career renaissance. I can't imagine anyone else as Clarisse. Andrews returned to Hollywood after fifteen years (and a botched operation that lost her her singing voice) to play the Queen with a combination of grace, poise and regality, while also giving her a sense of humour, which humanises her. Clarisse is a head of state, an important public figure, a political symbol; she is also, however, a grandmother, and (with a little help from Joe) she finds a way to balance her roles. Andrews and Hathaway's scenes together are some of the film's most enchanting. They make the perfect odd couple.

The rest of the cast rally around the two of them and each character – however small – makes an impression. My favourite is Mia's neighbour, the Emmy-winning but bad-mannered television writer Mr. Robutusen (Patrick Richwood), who is given to mournfully commenting on his day in stage directions. You could argue that the other major characters are all basically clichés, so it's up to the actors to liven them up. I love Heather Matarazzo's Lilly, who loves her best friend Mia and wants her to be a princess, but can't help it when 'the green monster of jealousy' enters her unbidden. I love Sandra Oh as the strict Vice Principal Gupta, who hilariously falls over herself trying to impress Clarisse, although she would be seen today as a mildly racist character: she's played by a Korean-origin actress and the first syllable of her name is pronounced to rhyme with 'pup'.

Then there's the seriously cute and floppy-haired Robert Schwartzman (of Coppola lineage) as Michael, Lilly's harmonica-playing brother, who's caught between being friendly and friendlier with Mia. And who wouldn't love Mia's mother Helen (Caroline Goodall)? She's a painter who also enjoys rock-climbing; she's a single mother who has raised her daughter in a large house with three levels, a massive studio and a pole to slither down. To bond, the two of them put on plastic overalls and throw darts at balloons filled with paint, attached to a large canvas. What's not to love?

Love is perhaps the greatest message of The Princess Diaries. For all the fantasy about tiaras, princess dreams, makeovers and foot-poppin' kisses, Mia reminds us to pause and tell our family and friends we love them. We mess up sometimes, but as long as we realise our mistakes and apologise – and make time to have fun – we'll be all right.