Apple TV+'s new dark comedy series Bad Sisters drops its first two episodes on August 19th. The story centers around the relationship between the Garvey sisters and their animosity towards their brother-in-law, who dies unexpectedly. When John Paul's (Claes Bang, The Northman) life insurance launches an investigation after his passing, the women are painted as prime suspects.

The series stars creator Sharon Horgan (Catastrophe), Anne-Marie Duff (The Salisbury Poisonings), Eva Birthistle (The Last Kingdom), Sarah Greene (Dublin Murders), and Eve Hewson (Behind her Eyes).

Related: How To Get Apple TV+ (& Which Platforms You Can Watch On)

Screen Rant chats with stars Claes Bang and Anne-Marie Duff about the complexity of their onscreen marriage.

Bad-Sisters-Claes-Bang-and-Anne-Marie-Duff

Screen Rant: I wanted to begin by asking, Anne-Marie, about your character. When we start Bad Sisters, she has lost her husband—played by Claes. This is a thriller and a dark comedy, so what is the grieving process going to look like for her this season?

Anne-Marie Duff: That's who you meet. A woman in deep grief right at the beginning of the show. So you don't really know who she is because she's kind of defined by her love of her late husband, isn't she? So we don't know who she is. She's kind of a mystery. She's to be unwrapped, isn't she? Well, she's one of the Garvey sisters and that's where she started. And then she becomes Mrs. John Paul Williams. And so the journey is the discovery of what that means. And sadly, what that has meant is that she is inside of a very coercive, unhealthy marriage. And what does that do to a woman? So that's kind of the journey of, I think, Season 1.

Screen Rant: Claes, that leads me to my question for you. A lot of the show is based around JP being this pretty unlikeable guy. The sisters are not fond of him. But as an actor, is it easier for you to kind of keep this character surface level? Or do you find yourself diving into different parts of him trying to figure out why he's acting the way he does?

Claes Bang: I actually, quite early on, thought finding out why he does what he does...I thought I had to make a decision, right? Otherwise, I'd go wrong, I think. So I think the thing that happens is that he feels that the bond and connection of these five Garvey sisters is a threat to him and his family. He feels all the time that someone is trying to take over his life.

I don't really know why that is, because it's not really something that is real. But he sees these monsters everywhere, doesn't he? And that sort of was the outset for me—that that's where it's gotten to. For some reason, he doesn't feel secure enough within himself to sort of be within that whole framework. So that's sort of why he does what he does, I think. That's the very short of it.

Screen Rant: Did you two work together off-screen to cultivate this relationship? Because you're obviously trying to get it to come across a certain way. Did you work with the director at all to achieve that?

Anne-Marie Duff: We had some rehearsal time before we started filming. And we did definitely sit down with Dearbhla, the director, and the two of us would chat, you know, try and work out what this marriage was. That was a massive priority for us. Because you know, the jig would be up if you didn't believe this marriage—if you didn't feel that that was the spinal column of the show. You need to really want to rescue Grace, and you need to despise her husband.

Claes Bang: And we come in so late. I mean, in a relationship where it's already gone astray. We did some rehearsals and a little bit of improvisation here and there to just try and—

Anne-Marie Duff: Fill in the blanks.

Claes Bang: Yeah. Because when you come in when there's no way back, we sort of need to know also what he was when he...if he wasn't good, it was at least better than what it is now. I think that was like the biggest challenge all the time to keep it real and true. And on that track where you could sort of also see, "Well, what a pity. If they could just do this and this and he could just stop doing all that bullsh*t, they could have a lovely marriage."

Anne-Marie Duff: Yeah, you needed to feel that, didn't you? To become exasperated enough with him.

Claes Bang: And just like, here and there, just see a little bit of something of, "Hey, this could have been really good if he would just relax."

Bad Sisters Synopsis

Bad Sisters Sarah Greene, Claes Bang, Anne-Marie Duff and Eva Birthistle

A delicious blend of both dark comedy and thriller, Bad Sisters follows the lives of the Garvey sisters, who are bound together by the premature death of their parents and a promise to always protect one another.

Check out our other interview with Bad Sisters star and creator Sharon Horgan as well as actresses Eva Birthistle & Sarah Greene..

Bad Sisters premieres August 19th on Apple TV+.