Laura Carmichael had been looking for a challenge - and she certainly found it in BBC One drama, The Secrets She Keeps. The Downton Abbey actress, who had shared her desire to play a psycho, stating "that would be really fun", landed the script for the Australian psychological thriller last year having spent time in Sydney with family.
"My boyfriend's brother lives there, so I had just been, which was another weird thing about this job, as when I was there, I was like, 'God, Sydney is great. I would love to come back'," recalls the 33-year-old over Zoom.
"So, when the script came in, it felt serendipitous. It's part of a plan."
Having already aired Down Under, the six-part series - an adaptation of author Michael Robotham's novel - casts Carmichael and Jessica De Gouw as two women who, despite being from two vastly different walks of life, hold one thing in common: explosive secrets.
While mummy blogger Meghan (De Gouw) is happily pregnant with her third child, lone shelf-stacker Agatha, also pregnant, is struggling to make ends meet. Cue an envious obsession which rapidly escalates into full-blown stalking.
"(Agatha) is this dark character, but unlike lots of thrillers it really focuses on her emotional journey," Carmichael says. "So, you understood the trauma that she's been through and what has led her to where she is."
"What drew me to the project, initially, was the fact the scripts were wonderful and female-centric and female-led," agrees De Gouw (32). "It just felt like it would be a really great experience."
As for the page-to-screen reworking, "I think that they've done a pretty good job of sticking with the novel," The Crown actress adds.
"Everyone has their secrets and everyone has these internal battles going on and so, from the outset, there's this undercurrent of unease from all the characters; they're all going through something."
As for the societal expectation put on women today, both stars, who donned fake bellies for the part, agree it's an important topic to address.
"It does feel like it's around a lot.
"It's that Instagram world that I can 100% relate to - and I am terrible at it!" Carmichael says.
"Some people can do it really well and are very authentically themselves, whereas I worry about the wording of a caption. I don't want to offend anyone."
"I think the expectations of women and motherhood are such an overwhelming thing," De Gouw adds, her character having been taken by the pull of social media.
"We try to really put women into boxes and (Meghan) is someone who feels like she doesn't fit and she's really struggling to find her place and her voice. She's exposing herself to the world, but it's a very cultivated version of herself.
"I sort of dug into that world of mummy bloggers and lifestyle influencers and it's a very strange world because they preach solidarity and community, but also there's this expectation of things that you should be buying and eating and the places you should be going."
Did filming out in Australia offer some release from an often-intense shoot? "It was interesting being somewhere where I didn't really know anyone," reasons Carmichael. "It was quite absorbing as I could go into the work of it at home and not have the usual distractions of real life. It was an amazing time. I loved it there."
For Perth-native De Gouw, it was a chance for her to return to a city she'd previously spent a lot of time in.
"I guess the best way to end the day is to have a debrief with the cast and with the directors - and usually have a glass of wine.
"I got to show Laura my version of Sydney and introduce her to my friends there. It's such a beautiful city, there's so much to do and see, so it was lovely."
Both back in London, what's next for the pair, tentatively speaking?
"I've had work put on hold, but it's sort of starting to look like it's picking up again, which will be wonderful," De Gouw says.
"But everybody has been in the same situation, so we've just got to take it as it comes."
"I really don't know," says Carmichael. "It feels like it will be an edging-out slowly, but in terms of thinking about the future, I guess, for me, it's fantasising about what I'd want to do next, but with no leads yet. It was such a joy to do something so different, so I want to do something different again next."
The Secrets She Keeps, BBC One, Monday, 9pm