On the verge of leaving drama school, Erin Doherty and her fellow students sat in a circle and predicted how each would be cast in their future careers. “I got ‘cowboy’,” Doherty exclaims, bemused. She looks sad for an instant. “I have never played a cowboy. They were really wrong.”

But think laterally: hard-riding, taciturn, loves horses, hates small talk, truly resents a posh frock. Yes, it’s a cowboy — but also Princess Anne. That’s the role Doherty, already a fan favourite as a stage actor, landed in the new run of The Crown, the award-gobbling Netflix sensation.

We speak several weeks before the media around the series goes full hoo-ha, aghast that Olivia Colman’s Queen may express a tendresse for a former beau, or that Doherty’s “frisky filly” of an Anne may be glimpsed in actual bed with an actual fella. Doherty doesn’t spill the tiniest teardrop diamond of a secret. She only laughs when I ask if we’ll see Anne’s wedding to Captain Mark Phillips.

“I’m not allowed to say. It’s horrible. I literally can’t tell you anything.” She giggles again. “It’s so intense. I’m excited that people will watch it, because then we can talk about it.”

Horribly Bashful? Maybe

In conversation, the Sussex-born Doherty is pure ebullience. Looking up in the Soho hotel bar where she is learning lines on her phone, she beams, I bounce — we pretty much break out the jazz hands. And then she declares she’s horribly bashful. I have to tell her I’m not getting that.

“I grew up very shy,” she insists. “I feel like theatre and acting is my one little area where I can do something. Everywhere else I have anxiety. I’m awful in social situations.”

The Crown is her first big screen role, and her awkwardness at landing amid British acting royalty — Colman, Helena Bonham Carter, the producer Stephen Daldry — helped her connect with the teenage Anne, shoved reluctantly into public life as the series begins.

“When I got the job, it was overwhelming: someone who had no idea what they were doing within this circle of people who knew everything. I felt like I didn’t fit — and I used that, because I think Anne felt like that, transitioning into the royal profile.”

Attention-dodging Anne flies beneath the radar for people of Doherty’s age (she’s 27). “I knew nothing about Anne,” she confirms. “She’s so closed. For a reason. She went through that experience of being in the public eye, and everyone ripping her to shreds. People tore her apart! I have an immense amount of sympathy for her — she’s just a teenage girl, trying to figure it out. Honest to God, I love her.”

On playing Anne: “I have an immense amount of sympathy for her — she’s just a teenage girl, trying to figure it out.”

This season takes Anne from her mid-teens through to her twenties — years of maximum awkwardness, but in a chokehold of royal protocol. “The whole premise of the royal family, now I’ve had a year of being in it, is so jarring. They’re not allowed to complain because they have everything, on the surface — but they’re still allowed to have feelings. Come on! I don’t know how they do it.” She and Josh O’Connor, playing the equally unhappy Prince Charles, sensed their characters chafing against constraints. “You feel the cement forming around you, and it makes you angry. But it’s so much fun to play.”

Doherty as Laura in The Glass Menagerie, in 2015. “I pushed my anxiety to 100.”

As seen in previous seasons, the royal childhoods were short on cuddles. “I think that does mess with your psychology,” Doherty says. “And learning that lesson from their mum, they close themselves off. It’s a cyclical thing.” Horses are Anne’s pressure-release valve: does Doherty view that as her ride to freedom? “Absolutely. I hadn’t really been on horses before, so the first time I was petrified. But after you become used to it and you’re galloping, it’s thrilling. It feels really primal. Nothing else exists, because you have to control a horse, so I think it would have been really therapeutic. She’s the first royal to compete professionally — it tells you so much about her. She was so desperate to take control of any part of her life that she could. She had no control, but horse riding was hers.”

Seeking the Voice

Doherty spent hours on YouTube, immersed in footage of the princess. It wasn’t so much the royal body language as the voice she sought. “It’s so particular. She’s kind of pushing it down: she’s got an oddly low voice. It goes when she’s older, so I think it’s psychological. She’s feeling restricted so she’s doing this to her throat. It then goes into your body and makes you really angry, because you feel someone forcing you to fit in a mould that is not yours. That affects everything.”

Much of this homework took place long before she landed the role. Doherty follows a tip from Breaking Bad’s Bryan Cranston, who believes actors should approach auditions as if it’s their one chance to play a character. “Just prep it like it’s your one-night-only and then you feel fulfilled, because regardless of whether you get it, you did it.” Her two auditions were followed by agonising silence. She tried not to think about Anne, “because the disappointment would be heartbreaking. When I found out, I remember my face becoming fire. Honestly, I still don’t quite believe it.”

“Becoming fire” is very Erin. Her gaze is direct, her oval face a rapid-response unit of enthusiasm. Thin gold chains catch the light around her neck. Theatre insiders have responded to her searing immediacy since she graduated from Bristol Old Vic Theatre School in 2015. In January, this paper tipped her as a face to watch, while in 2018 Michael Billington, veteran critic at The Guardian, declared she has “star quality. I think that in a year or two’s time, everyone will be talking about this woman. She has the most amazingly flickering eyes, which radiate curiosity and liveliness.”

Doherty at the premiere of Season Three of The Crown earlier this month in London.

Doherty’s characters are often tugged between anguish and a quixotic resilience. She was the catastrophically shy Laura in The Glass Menagerie (“I pushed my anxiety to 100, until it becomes debilitating”); a frazzled Amazon-style warehouse drudge in Katherine Soper’s Wish List. Earlier this year she was incandescent as an orphaned twin in Ross Willis’s fantastical two-hander Wolfie at Theatre503 in London. However desperate, there’s a sympathetic relish in Doherty’s portrayals: you feel their pulse, beating with your own. “I get such a buzz,” she confirms. “I find it quite freeing, because in my personal life I feel quite overwhelmed by it all.”

Roll of the Dice

As well as going hell for leather at auditions, another of Doherty’s secret weapons is a little dice from a Christmas cracker. It relates to her “biggest epiphany” at drama school, when her teacher John Hartog told students to abandon their search for the perfect performance. “‘Each show is its own thing,’” she remembers him saying. It released her, she says. “You remove all the pressure and get to have fun and be present. I whittled that down to this weird dice thing.” Before each performance, she rolls her cracker dice, “just to remind myself no one knows what’s going to come out. It’s not always going to land on the one. Let it be whatever it will be.”

So far, each roll of the dice in Doherty’s career has paid off. Does she trust her instincts? “Well, they’ve led me here. Now I’m royal!” She’s already filming the next season of The Crown, with its unusually lavish resources.

“It’s unlike anything. On my first couple of days, Olivia Colman — the nicest, most normal person — kept coming up to me and going, ‘Don’t get used to this. This is unlike anything. This is not a normal job.’ I’m having a great time, but you have to check yourself.”

What also isn’t normal, for an actor who usually swims in the small but intense pond of British theatre, is becoming part of the national conversation. Does she look forward to the attention? “I had to forget about that. You don’t go into a play thinking about the number of people who will watch or have an opinion on it. This is the polar opposite. With Anne, the reality is that people will say, ‘She didn’t do that.’ That comes with the territory of playing a real person. But we also have to respect that we’re doing [the screenwriter] Peter Morgan’s version of these people’s lives — it is a drama. And this is Erin’s version of Princess Anne. That’s what I’m employed to do.” She tries to sum up the boggling unexpectedness of it all, and ends up giggling with delight. “It’s just so silly!”

And after Anne? She’s still thinking of that slow-burning cowboy. “I’d love to play something proper gritty, especially after a princess. I want to be muddy and gross. That’s what I want to do next.”