Amanda Seyfried is always up for a challenge. In The Testament of Ann Lee, the 40-year-old American actor not only dances and sings about celibacy, but she embodies a female Jesus who’s so charismatic she launches a religious movement. Directed by Mona Fastvold, the 18th century-set, 35mm-shot musical is a mesmerising retelling of how a young woman, Ann Lee, left Manchester to form the Shakers in rural New York. Unless you ingested magic mushrooms while watching Seyfried in Mamma Mia!, you’ve never seen anything like it before.

After all, The Testament of Ann Lee defies genre definitions. It’s a forward-thinking movie about equality set in the past. It’s a biopic that delves into magical realism. It’s an Oscar-y premise that’s so experimental it’s scared off Oscar voters. It’s arguably not even a musical: the diligently choreographed songs are part of how the Shakers (initially called the Shaking Quakers) pray on a daily basis.

In a London hotel in December, I ask Seyfried and Fastvold if to be a brilliant actor in weird films you need to be a weird person yourself. “Definitely,” says Fastvold. “I think so,” says Seyfried, who’s so relaxed she earlier took off her shoes to put her feet up on the table. “The weirdness comes from the appreciation for the abstract, and the part of life that’s absurd. The ego needs to go out the window for singing, for every artistic expression. You have to be able to go where you’re asked to go – and then go further. When I was speaking in tongues in this movie, I could pretty much do anything. It’s hard to be fearless, but when you open that gate, it’s euphoric.”

In Mean Girls and First Reformed, Seyfried played memorable side characters. She’s previously lamented that when she’s cast as a lead in a film, it’s usually the less juicy role. However, Ann Lee, who’s perceived to be the second coming, is in practically every scene. “She’s so multifaceted,” says Seyfried. “If you can relate to a character, and they get weird, it opens you up.”

“Everyone’s peculiar if you get to know them,” says Fastvold. “The key is to take the audience on a journey that feels not weird, but it feels human. Her strangeness feels relatable. Even if you don’t agree with her choices, you understand them.”

Fastvold, a 44-year-old Norwegian filmmaker, wrote the screenplay with her partner, Brady Corbet. Like The Brutalist, which Fastvold also cowrote, The Testament of Ann Lee is an epic period drama somehow shot for under $10 million. One sequence on a ship was accomplished by the cast swaying left and right on stationary floorboards. Elsewhere, the aesthetic pleasures are heightened if you watch it, like I did, projected on 70mm. Fastvold gets lost on such a long tangent about celluloid capturing the details in blacks and blues that Seyfried interjects with: “OK, Brady! I’m kidding. But that’s what you guys talk about at four in the morning – lenses. The other night in the car, Brady was talking to Joe [Alwyn] about… I don’t even know.”

“At the time, you were your husband’s property. Celibacy was a way of breaking apart the idea of what relationships between men and women are“

“It’s a new camera we’re trying to create with some technology,” says Fastvold.

As a child, Ann feels unfulfilled by Christianity. Her curiosity in God, though, is sparked by a visit to purging sessions run by Jane Wardley (Stacy Martin): through flailing arms and sharp exhales of breath, the body spiritually cleanses itself. In crowded rooms, the prayers look spellbinding, fun, and exhausting. They’re like dance floors but with a religious bent: it’s during one session that Ann finds herself drawn to Abraham (Christopher Abbott), the pair shaking their limbs and hips in close proximity.

“There’s descriptions of Shakers dancing for four days that end with them passing out,” says Fastvold. “But ultimately all the movement is prayer. It’s about ridding yourself of whatever sin, guilt, or pain is in your body, and helping others. You take their pain, pull it into your body, and push it out of you.”

“The scary part is that we don’t have footage of anybody,” says Seyfried. “Not until the 1900s. You have a lot of liberties, but you want to stay true to something. There’s nothing about her that’s like me in the way I move naturally.”

Ann is such an enigma, you never quite know what’s going on behind Seyfried’s famously wide eyes. As a child, she’s disgusted by the sight of her parents fornicating. Married to Abraham, Ann gives birth to four children who all die within months. Taking disciples to America, Ann claims that sex creates distance from God, and thus they should all adhere to celibacy. In the same breath, Ann proposes a society where every race and gender are equal.

“Celibacy is insane,” says Seyfried. “It’s bullshit. But the film is timely. Everything she preached was to bring people together, and to create a utopian society where everyone is equal. The celibacy aspect comes from her trauma. Having sex, having a baby, and losing it – I understand that. But the underlying thing is: how do we protect and nurture each other? Community is everything. Socialism is this beautiful idea, but we all have to promise each other that we’re going to do our best.”

“At the time, you were your husband’s property,” says Fastvold. “Celibacy was a way of breaking apart the idea of what relationships between men and women are. It’s like, ‘I’m going to take out sexuality, childbirth, and pregnancy. I’m going to create an even playing field.’ My interpretation is, it spawned from great trauma, but others followed because they felt like a brother and sister can be equal. It’s like children without sexuality who are friends and can respect each other.”

After Ann’s death, word spread about her visions, and the Era of Manifestations (1837 to the 1850s) saw up to 4,000 Shakers joining the cause. However, as the film’s end credits indicate, there were only “two believers” in early 2025. Fastvold resisted contacting the pair before the shoot. “I’d have been too scared of doing anything to offend them, which I hope I didn’t,” she says. “I love the story of Mother Ann Lee, and wanted to tell it in a respectful way. But I’m not a Shaker, and I’m not a believer. It’s an interpretation.”

In the gap between the Venice premiere and our interview, the number increased by 50 per cent to three believers. Fastvold explains that the end credits were hand-painted, shot on film, and scanned back in. “It took a long time to change the ‘two’ to ‘three’ [for the new print],” says Seyfried. “It had to be painted.”

Just as enthralling are the opening credits that space out text around the frame alongside spirit drawings. Combined with an early musical number, the film hypnotises the viewer within its first 10 minutes. Upon hearing my description, Fastvold notes that viewers tell her the introduction makes them feel like they’re high. “The film’s set in the past and feels like it’s on drugs,” says Seyfried. “It’s psychedelic.” Fastvold imitates the breathing exercises, explaining, “If you do that long enough, you start feeling high.”

“I was able to experience the exhaustion of dancing for hours and hours and hours in the heat,” says Seyfried. “You hit a new height of energy because you get a second wind, and it’s so physical that you almost feel like you can fly. And there’s no drugs in that, except the movement.”

The Testament of Ann Lee is out in UK cinemas now.