Venice Film Festival: How Does Kristen Stewart Play Princess Diana?

The star of “Spencer” may be one of the few actresses with an inkling of what it’s like to be so often hounded by the paparazzi.

While watching the new film “Spencer,” which premiered Friday at the Venice Film Festival, I kept pondering Kristen Stewart’s long, unlikely association with the fashion house Chanel.

The actress has been an ambassador for Chanel since 2013 when she was fresh off the “Twilight” series. At first blush, it might have seemed like a bad pairing: In her off-hours, the insouciant Stewart is more of a jeans-and-Converse type, while Chanel is high-end clothing that can verge, without the proper styling, on prim and fusty.

But something fascinating happens when Stewart dons those tweed jackets. Because they aren’t a natural fit for her, she wears them more provocatively: Sometimes they’re slung over her shoulders with the casual cool of a leather jacket, or they’re fastened only at the top with nothing on underneath. Instead of becoming the classic ideal of a Chanel woman, Stewart wrests that ideal toward her, and the distance that remains between those two extremes is the thing that catches and keeps your eye.

Something rather similar happens in “Spencer,” in which Stewart plays Princess Diana. Already, your mind may be reeling at that potentially calamitous collision of famous figures: A slouchy American star as the people’s princess of Wales? How can an iconoclast like Stewart play the icon that was Diana?

The tip-off comes early, during the film’s opening sequence. It’s Christmas Eve at Sandringham House, where the royal family has gone to spend the holidays. Their breakfasts, lunches and dinners will be executed with all the precision of a military manoeuvre because … well, it literally is a military manoeuvre, with soldiers pressed into service to transport fresh produce and lobsters to Sandringham in camo-clad trucks.

Meanwhile, as the kitchen staff is standing at firm attention, Princess Diana is lost. We meet her in a BMW convertible as she stares at her map, miles off course in the countryside with no security detail to keep her on track. Her first line includes a muttered expletive and her next, offered to a star-struck roadside clerk, is both plain and plaintive: “Where am I?” Once she gets to Sandringham, she’ll be even more lost.

So if you’re wondering how a star like Stewart fits into a British drawing-room drama, the answer is that she’s not really supposed to: Diana doesn’t, after all. The princess goes to great lengths to avoid the rest of the royal family, but Stewart as Diana thrives in those encounters when the contrast between her and the stiff-lipped British cast becomes so palpable that she’s reduced to a trembling mess.

Does Stewart nail the voice, the accent, the posture, the star quality? Well, it’s not really one-to-one accuracy that compels us while watching “Spencer”: As with those Chanel jackets, Stewart is pulled toward Diana and Diana is pulled toward her. The actress is working in a different, higher voice register here, and she has incorporated some of Diana’s physical tics into her own repertoire, including the way the princess would tuck her chin into her shoulder, her upturned eyes either fearful or coy depending on who’s looking.