The first thing to know about BBC America's new spy thriller Killing Eve is that the title can be read more than one way.

"You can make killing an adjective," Sandra Oh, the Grey's Anatomy veteran who stars as Eve Polastri, said in an interview in January. Introduced in the 8 p.m. Sunday premiere as an underchallenged MI5 security officer in London with a secret obsession (and an American accent), Eve soon finds herself tracking an international assassin who calls herself Villanelle — while trying to stay alive through the eight-episode first season (it's already been renewed for a second).

At first glance, Jodie Comer (The White Princess) might seem to be having all the fun as Villanelle — her character, almost certainly a psychopath, enjoys the work more than Bill Hader's stagestruck hit man does in HBO's new comedy Barry — but don't count out Oh's Eve.

Eve's "darkness is not apparent at the very beginning," Oh  said. "But I think as her relationship [with Villanelle] continues to grow, as she searches for this killer, she really discovers what's inside of herself. … So [if ] your question is, 'Would it be more fun to play the psychopath?' Well, who says I'm not?"

Adapted by Phoebe Waller-Bridge (Fleabag) from novellas by Luke Jennings that are collected in the book Codename Villanelle, Killing Eve isn't just a showcase for these two actresses. And the cast, the 46-year-old Oh noted, includes at least one woman each "in her 20s, 30s, 40s, and 50s."

At 59, Fiona Shaw (True Blood), who costars as the veteran spy who first spots Eve's potential, plays a character who is "vibrant, sexual, powerful, and mysterious," Oh said.

But then women are also running the show, she said.

"There's a lot of work to do … in increasing the presence and diversity of women and people of color" on screen and behind the scenes in the entertainment industry, she said. "But it's like when people are asking for the change, and waiting and wanting the change, I realize that I just this past six months [was] being part of it. And it's exceptionally satisfying."

Jodie Comer (left) as Villanelle and Sandra Oh as Eve Polastri in a scene from BBC America’s “Killing Eve.”
BBC America
Jodie Comer (left) as Villanelle and Sandra Oh as Eve Polastri in a scene from BBC America’s “Killing Eve.”

Like Starz's Counterpart, the parallel-universe series with J.K. Simmons that wrapped up its first season April 1, Killing Eve is  a spy drama featuring a middle-aged character who's long been underestimated.

Read more: J.K. Simmons talks about starring opposite himself in Starz's "Counterpart"

"That part I was extremely interested in. I like the fact that Eve, in all  her kind of messiness, is hunting an international killer with her handbag," Oh said, laughing.

"Kind of walking down the street with her handbag. There's something I really love about that, because it's not sleek, it's not suddenly like a Jason Bourne movie. There are elements of it that I really love, which is the international locations, the overall style of it, or genre of it. But the fact that you have a middle-aged lady who is determined, and doesn't know exactly what she is doing — that really fascinated me."

It also allows viewers to see what it might take, beyond James Bond's endless gadgets, to do this kind of work. "She just has good instincts and general sense. Eve doesn't have any super-spy skills, you know what I mean? But she has a head on her shoulders. And she's determined," Oh said.

Between Grey's ultraconfident surgeon Cristina Yang —  Oh left the cast in 2014 — and Eve, "I played a lot of different people and different characters. People who were nasty, people who were loving, people who were vulnerable,"  said Oh, whose recent work included an arc in the final season of ABC's American Crime.

"I like Eve's vulnerability, because I  think she has a lot. I spent a lot of this show being scared. And I thought that was also very interesting. It's not so much that I consciously seek characters that are determined or confident. I'm interested in what takes them to what they want. If I can relate to what a character wants, I will give my all to get that character … what they want," she said.

Though she has no regrets about leaving Cristina behind ("It was absolutely the right decision for me"), Oh said she's extremely pleased by the endurance of Grey's Anatomy, nearing the close of its 14th season on ABC with the end not yet in sight (star Ellen Pompeo has signed a deal for two more seasons).

"Because I do think that Grey's has carved out a very unique place in television. Also because it straddles two different eras of television. When we started it, it was still network. You watched something weekly. It was almost like analog television, you know? Coming through a transition of how people watch it, I have generations of people who come up to me. It constantly changes. It goes from this group of people to now this group of people. How are they seeing it now? They weren't alive or whatever" when it started, she said. "So what show can you say has that power, and also just came along at that right moment? It had all these magical, lightning-in-a-bottle elements, and that's what is continuing to give it its longevity. I mean, I think it's amazing. Because people are very loyal."

And whatever happens to Eve, Oh has come to realize there's no killing Cristina.

"Every year or so, someone close to me is going to come up and say, 'So I heard you're coming back,' and I've always been so confused by that," Oh said, laughing. "What I'm learning that it tells me is that it still has its life, and I appreciate that the life of this character, Cristina … is still a part of that world."

"Killing Eve." 8 p.m. Sunday, BBC America.