To portray Helen Webb in the unconventional London-set series Black Doves, two-time Oscar nominee Keira Knightley found herself immersed in the psyche of the secret agent. After a decade in the employ of a top secret organization, Helen is grappling with who she really is and what she wants from life. While keeping up her facade as the happily married wife of a conservative politician and stay-at-home mom of two, she’s secretly mourning the death of her lover and preparing to take revenge on those responsible for his murder — a tricky balancing act to say the least.

“The image that I kept getting of Helen was the comedy and tragedy mask,” Knightley says. “Helen is whatever she needs to be. I feel like she’s a more extreme version of the way we all are, right? We all have one face for our kids. We have another face at work. We have another face for our friends. Everybody understands the feeling [when] something inside that is not being fed needs to get out.” 

That might sound like the gender-flipped setup for a straightforward spy thriller, however, James Bond this is not. While Black Doves raises intriguing questions about the mysteries of attraction and the slippery nature of identity, the six-episode series also sees Helen embark on what Knightley describes as a “mad, deranged killing spree with her best friend who’s an assassin” during England’s Christmas holiday. It’s a cerebral, action-packed thriller about a pair of longtime pals who comically quarrel like siblings as they try to outrun the danger that seems to follow them wherever they turn. “The juxtaposition of those things was quite excellent,” Knightley says. “That’s the reason that I wanted to work on this. The whole concept made me laugh.”

Vintage tank with trousers by Chanel

Knightley burst onto the world stage at age 16 playing a spirited footballer in the lighthearted indie hit Bend It Like Beckham. She went on to star in the blockbuster Pirates of the Caribbean: The Curse of the Black Pearl and its sequels as well as classic British rom-com Love Actually, but it was her work in prestige fare that garnered significant acclaim.

Her luminous screen presence, fierce intelligence, and ability to simultaneously project strength and vulnerability made Knightley a natural fit for literary heroine Elizabeth Bennet in Joe Wright’s 2005 Pride & Prejudice, for which she earned a Best Actress Academy Award nomination. Lauded turns in a range of dramas followed, with Knightley starring in Atonement, Never Let Me Go, A Dangerous Method, and Anna Karenina, among other films. She earned her second Oscar nom for her supporting role as World War II codebreaker Joan Clarke in The Imitation Game.

Last year, she played Loretta McLaughlin, the real-life Boston Globe journalist (and mother of three) credited with helping catch a notorious serial killer, in the true crime thriller Boston Strangler. In a broad sense, it was a logical precursor to her Black Doves role, with both characters’ personal responsibilities in conflict with the demands of their professions.

“When you think about all those John le Carré spy novels, the characters are often going through some sort of identity crisis, struggling with living multiple lives and what’s true and what isn’t,” Knightley says. “Helen sits very much within that framework. Once you’ve been in a marriage where you are deceiving your husband for at least 10 years, I should imagine that there is somewhere a crisis of conscience.”

Black Doves opens with a cascading set of mysteries that only deepens as the season unfolds. A civil servant named Jason (Andrew Koji) is assassinated in public the same night two other seemingly unrelated civilians are killed, though the crime is secondary to the day’s more urgent news — the Chinese ambassador has died under suspicious circumstances, his daughter has gone missing, and diplomatic tensions are high. Soon, it’s revealed that Knightley’s Helen had struck up an extramarital affair with Jason, unbeknownst to her husband Wallace (Andrew Buchan), the U.K.’s defense secretary.

“Part of the story of the series is her looking at this person who is suddenly taken away from her and questioning whether the whole thing was real in any way, questioning her own motives for the affair,” Knightley says. “I quite liked the idea of memory [and how you think about] past relationships, and you go, Oh, what was that about? She didn’t have to go off with Jason — that is her trying to play with fire because she’s a creature that needs to play with fire.”

Reeling from grief, Helen is determined to root out the shooter, but her actions carry a great deal of risk, both for herself and for the clandestine organization she works for. Concerned by Helen’s recklessness, her handler Reed (Sarah Lancashire) sends for Sam (Ben Whishaw), a ruthlessly efficient killer for hire who’s been away from London’s shadowy underworld for seven years. As Helen’s only real confidante, Sam is tasked with keeping watch over her, ensuring that her identity as a secret agent isn’t disclosed. But Sam has secrets of his own that threaten to come back to haunt him.

The old friends trade barbs, but they truly understand and appreciate one another’s dysfunctional psychology, Knightley says. “It’s honoring the lineage of the spy genre in the way that you have these two characters that can be quite melancholy . . . [but] they can talk to each other and allow all their monstrous, horrific, wonderful sides to be shown,” says Knightley of the characters’ strong rapport. “They can be utterly their own extreme, weird creatures. There’s this beautiful, very strange friendship in the center of this madness that, to me, the whole thing was about.”

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For Black Doves’ creator Joe Barton (The Lazarus Project), Knightley’s unique combination of grace and gravitas made her the ideal choice to play Helen — indeed, she might be one of the few actors on the planet who can convincingly portray a well-heeled Brit on the fast track toward a future at 10 Downing Street, a lethal killer on a mission of vengeance, and the loyal best friend to the self-described “triggerman” played by a droll Whishaw.

Barton was thrilled that she not only agreed to star but committed early, becoming a true creative partner on the series. After sending the script to Knightley’s agent, “literally five days later, I was in a coffee shop with her chatting about it,” Barton says. “At that point, it was just the two of us and this screenplay that had been written very quickly. Keira was a day one partner in the whole process.”

Whishaw was keen to work with Knightley and the actor, an Emmy winner for his supporting performance in the miniseries A Very English Scandal, says that he found the idea of a spy thriller centering the friendship between a woman and a gay man to be singular and surprising. “It’s a really interesting relationship they have,” Whishaw says of Helen and Sam. “It’s an unusual kind of love, but it’s love. I think they recognize each other. They recognize that they’re somehow very different, but they’re also the same. They’re complementary, and they have this intimacy that they don’t have with anybody else.”

Vintage T-shirt and belt are Keira’s own with Jeans by Citizens of Humanity

Filmed in England during the winter months, Black Doves presented Knightley with one of the most challenging projects of her career as she set out to navigate Helen’s inner tumult. Toggling from cheerful housewife and mum to heartbroken, vengeful agent and supportive best friend — making Helen feel whole and complete — was a delicious, meaty challenge, she says. Adding to the complexity of the task was the degree of ambiguity surrounding the episodes that would conclude the season, as Barton had not yet finalized the last episodes when cameras initially rolled.

“I’ve never done a project where you go, I actually don’t know what the end of this is, so that was a new experience,” Knightley says with a laugh. That prompted her to develop a new way of working, emphasizing improvisation and quick thinking rather than intensive research and planning. “I had to let go of all the ways that I would normally prepare for something and go, O.K., we’re gonna go on this mad journey, which feels quite appropriate for the mad journey of the story. The way I got my head around it was going, This is jazz.”

Setting out on her new mission, the actor found that she thrived in the live-wire environment, and that her co-stars did as well — a good thing, as Black Doves is already set for a second season. Knightley, for one, says she’s ready. “As far as an acting exercise goes, this was pure instinct,” she says. “It was my instinct meeting Ben’s instinct. You’ve got actors who are working from some great dialogue, and the premise is great. Everybody came in and they were up for the challenge. I think everyone really got off on the silliness of it, the fact that it’s a heightened reality.”

Serious, silly, and sincere? The spy game has never been quite this much fun.