(This story contains spoilers for the finale of The perfect couple.)

In hindsight, Dakota Fanning’s line from the first trailer for the Netflix miniseries – “The key to this family is staying on the edge” – was very telling. But perhaps not in the way her character intended.

Neither the victim nor the murderer in The perfect couple were ultimately part of the core Winbury family. And if you ignore those last-minute revelations – Nicole Kidman’s WASPy matriarch revealed that she had worked as an escort in a previous life and met her husband, Liev Schreiber’s old womanizer, as a client – the clan escaped virtually unscathed. It was the would-be daughter-in-law’s maid of honor (Meghann Fahy) who lost her life, and daughter-in-law Abby (Fanning) who apparently committed the act in a wild game to ensure her unfaithful husband could collect on his trust fund.

Fanning missed the UK and US premieres of The perfect couple for their Australian shoot of the upcoming Peacock miniseries All their fault. But the Ripley The Emmy nominee for Best Supporting Actress in a Miniseries joined Zoom last week to talk about her lead role in the series – including her baby bump, which led the internet to question whether she was actually pregnant during filming.

Your fake pregnancy belly was so convincing that I actually googled whether you had recently had a baby.

It was an incredible prosthetic. I didn’t wear it the whole time – I wore another one under clothes – but there was no way she was going to wear a one-piece to the pool. It had to be a bikini and you had to show the stomach. But we really had to get it right. It was the most incredible thing I’d ever seen. And it wasn’t glued on, I put it on like a corset so it wrapped around my whole body and tied at the back. I lay there so you could never see my back; it was so seamless from every angle. It’s wild. People on set stared at me nonstop that day and then apologized for staring. Nobody could believe the thing. I loved it.

For an ensemble piece like this, The Murderer is naturally one of the most exciting options. How did this honor come about?

I had already worked with (director) Susanne (Bier) on The First Ladyand we developed a really close relationship. She called me about the role, gave me the bullet points, and the final bullet point was that she’s the killer. I sat in the kitchen, listened to her describe it, and just said, “Yeah, whatever you want.” And at that point, Nicole was the only other person officially cast – so I was back in. (Laughs.) Then a lot of things fell into place. Eve (Hewson) has been one of my closest friends for years. I’d never met Jack Reynor, but we’d almost worked together at some points over the years. So there was a kind of camaraderie between us and everything came together in such a beautiful way.

The success of such a film depends entirely on whether at least some doubt is raised about the innocence of almost all the characters. As the guilty party, how did you deal with this balancing act?

There were certain moments where Susanne said, “OK, do a take where you’re the murderer.” We shot a lot of stuff multiple times, especially in the beginning. The further you go, the clearer everything becomes and the easier it becomes. You get the instinct for the character. But in the beginning it was a lot about figuring out what’s going on. The part of Abby that we focused on the most was that after she committed the murder, she forgot that she was the murderer. In a way, she’s disconnected from it and compartmentalized it in a sociopathic, pathological way. It almost doesn’t exist in her mind.

This ability to differentiate probably helps her endure her horrible husband.

Absolutely! You have to be a world-famous rocker to even be part of the family, but Jack and I – that dynamic, doing those scenes with him – we became super close. He is the best and we often felt like we were doing our own, separate show. We called it The worst couple. We had our own storyline at all times, in every scene. It was a whole piece.

As far as revelations go, there’s the killer and… that unexpected revelation that Nicole and Liev’s characters began their relationship as an escort and a client. This is arguably the biggest twist and almost seems to break Abby.

I just thought it was hilarious – the way that scene plays out and looking at it from Abby’s perspective. The first moment when she drops the mic is that the Monet is fake. It’s devastating for her. Then they say they met in a bar and she says, “Well, Tom and I met in a bar.” She thought she could salvage it. When she realizes the extent of it, she freaks out. It’s all a facade. It’s not what she thought. She was trying to salvage the thing, but what was she even trying to salvage? In that moment with the fake Monet, you can just see it crumbling for her. That’s how I feel about it as a character though. As an audience member? It’s so funny. Liev says, “I never paid!” And Nicole says, “You paid! Three times!” What’s going on!?

In the advertisements for this show there was a lot of talk about the dance number in the opening credits. Were you part of the rebellious cult or were you involved?

First of all, the actors had a WhatsApp chat during filming. It was not created Because of the dance. We had that from day one. And I was on the rebellious side… just scared that I wouldn’t be able to do the dance. I just thought I can’t do it. So we were all torn over the Christmas break because we were shooting in January. But when we had that rehearsal day and I found out that I could physically do the dance, I thought, “OK, fine.” When I talked to Susanne about the intention behind it, I also found out that it was to create this kind of surreal, heightened tone. To immediately signal to the viewer that we are doing something crazy here. Then it was just fun because I don’t think I will ever find myself in that situation again. And I really wanted to keep watching Liev have to do that.

It probably helped that it happened at the very end of filming.

It was literally the last thing I filmed. So we all knew each other so well. We had done the part on Cape Cod. We had filmed in London. Those were the last few days in LA, and I’m not exaggerating when I say we all became so close.

I admit that the opening credits confused me at first – but after a few episodes it felt like The White Lotus Opener. That really pumped me up.

I know! It’s actually about preparing you for the episode.