The final season premiere of “Killing Eve” includes an poignant homage to Baz Luhrmann’s “Romeo + Juilet” as Villanelle (Jodie Comer) and Eve Polastri (Sandra Oh) view each other from opposite sides of an aquarium.

“It’s not a coincidence,” Oh told senior entertainment writer Angelique Jackson in Variety’s Streaming Room, confirming that there’s “a bunch of film references” that were baked into the new season to create visual (and familiar) dynamics. “There is this tank of water between these two women… [They’re] not really being able to hear each other across it, and there’s beautiful symbolism in that.”

Comer also discussed Eve and Villanelle’s reunion — which included Eve slapping Villanelle across the face.

“We did it for real… I was like, ‘No, I want you to slap me.’ [Oh] was like, ‘Really?’” joked Comer, addressing the shift in dynamic between the series’ lead characters.

When Villanelle “sees that Eve really means what it is that she’s saying, that’s quite alarming for Villanelle, [it] was the last thing that she was expecting,” Comer explained. ”That’s what’s so interesting about the way the story progresses — you just don’t see where it’s going to go.”

Comer also relished her transformation into Jesus Nelle (a.k.a. the “Villanelle Vision”).

“What Vision represented was almost the worst part of her is dressing up in disguise trying to lure her back to the dark side,” she explained. “Her fluidity, and her sexuality, and her celebration of fashion and all of that came into play. I have to say, it’s the sexiest I’ve ever felt, in my knee-high boots and my beard. There was something really satisfying about it.”

The fourth and final season of “Killing Eve” began Sunday, with the airing of its premiere episode, titled “Just Dunk Me, “a reference to Villanelle’s baptism scene. The British spy thriller series follows Villanelle, a talented assassin, and Eve, a British intelligence officer, as their obsessions with each other grow while the two play a gripping game of cat and mouse. But the cast underlines how far the characters have evolved over the course of the series and particularly since fans last saw them.

Oh pointed to the bridge scene in the final moments of Season 3. “They have a moment to kind of rest together. They have a moment to actually realize that, ‘We’re on the same side… The thing that has caused us the greatest amount of grief actually might not necessarily be each other. It’s that institution,’” said Oh. “Particularly in our final season, I really wanted to see Eve and Villanelle come to a place of possibility and a place of intimacy.”

Season 4 picks up with a jump forward in time — which executive producer Sally Woodward Gentle notes was necessary for the change expressed in each of the characters’ lives (including Eve’s incredible fighting skills featured in the latest episode’s opening scene and Villanelle’s attempt to find redemption in the church).

“Eve and Villanelle left each other on that bridge, at the end of [Season 3], really questioning who they were… and what life meant since they’d had each other in their worlds. We thought it was more surprising to move on to where they’ve both gone [since],” said Gentle. “There are some really interesting, really brilliant turns that happen in this season as we go on — but to rift them and pull them apart more than just the space of a week, I think, was a useful thing to do.”

Interestingly, Gentle and Comer had different estimations for just how long it’d been since Villaneve were face to face. While Gentle estimated it’d been eight or nine months between scenes, Comer had imagined a 5 or 6 month jump.

“I was like, ‘Yes, she’s committed to this, but there’s no way she would last a year and a half in this church,” she explains. “She’s trying, but I couldn’t see her having kept that up for so long.

Hear more from Oh, Comer, Gentle, Kim Bodnia (who dishes on Konstantin’s transition into politics and what it was like to get shot by Eve) and Fiona Shaw (who unpacks Carolyn Martens’ search for answers about Kenny’s assassination and her surprising replacement at MI6) in the conversation above.

“Killing Eve” airs Sundays on AMC Plus and BBC America.