Stewart is such inspired casting that she makes all this eccentric nonsense watchable. She’s been practising Diana’s signature moves for years – dipped head, hunched shoulders – and she certainly knows what it’s like to put up with intrusive tabloid photographers. She also looks suitably fabulous in the many outfits that Diana is required to wear over the long weekend. And unlike Watts’s performance in 2013, hers doesn’t seem distractingly like an impersonation. Mind you, she delivers all her lines in little bursts of hissing whispers, so if you don’t see it with English subtitles, as its first audiences did at the Venice Film Festival, you might not understand more than half of what she says.
The effect is a bit odd, but there are lots of odd things in the film, not least the tone and the pacing, which lurch around like someone who’s had too much after-dinner port. Between Jonny Greenwood’s squalling jazz soundtrack, the hallucinations, and the blush-making sexual confessions, Spencer is a folly that wobbles between the bold and the bad, the disturbingly gothic and the just plain silly. In some scenes, it’s heart-rending in its depiction of Diana’s self-harm and bulimia. In others, it’s almost as risible as the Diana biopic from 2013, and that’s saying something. I didn’t know any more about Diana afterwards than I did beforehand, but I can’t say I didn’t enjoy it. This is a film that echoes The Shining at the start and 2001: A Space Odyssey at the end. The Crown Christmas Special it ain’t.
★★★☆☆
Love film and TV? Join BBC Culture Film and TV Club on Facebook, a community for cinephiles all over the world.
If you would like to comment on this story or anything else you have seen on BBC Culture, head over to our Facebook page or message us on Twitter.
And if you liked this story, sign up for the weekly bbc.com features newsletter, called The Essential List. A handpicked selection of stories from BBC Future, Culture, Worklife and Travel, delivered to your inbox every Friday.