Jessica Plummer on The Girl Before: 'I joked when I left EastEnders I wanted to do something light-hearted'

"I sound like a broken record, but I just found it such an honour to be able to speak to an audience as large as the EastEnders following," she explains, on being involved in the aforementioned storyline, which saw Chantelle murdered by her abusive husband Gray Atkins.

"Although it was tricky and challenging as an actor, we wanted to show that sadly sometimes that does happen in real life – and being able to do that and potentially help people out of their real-life situations made it all worth it.

"And I think it's similar with being Emma Matthews in The Girl Before," she adds. "I just think if it can speak to somebody maybe in that situation to do something differently or do something similar or whatever the case may be, it just makes it all worth it. Even if you can't necessarily directly relate to the specific trauma, there are always ways that everybody can relate to somebody going through a hard time in one way or another."

The Girl Before is adapted by JP Delaney from his bestselling novel of the same name, albeit with a couple of alterations from the source material. And Plummer says that while she originally intended to read the book in preparation for the role, she eventually came to the conclusion that it made more sense to view the novel and the series as two separate things – although she says she'll finally sit down to read the book after the show has aired.

But her preparation for the role did involve a lot of research around responses to trauma, and she explains how production company 42 set up a meeting with a therapist so that she could get a deeper understanding of her character's state of mind. "They got me in contact with a therapist that Emma Matthews would have probably been going to see," she says. "And just speaking about things that she might have felt or conversations that she might be having with her therapist, just trying to bring it to life."

But how much can Plummer relate to some of the choices Emma makes in the series? The show revolves around an important decision she makes in the very first episode, where, along with her partner Simon (Ben Hardy), she opts to move into a stunning new apartment that comes with some extremely draconian stipulations, not to mention the threat of constant surveillance. Given how shifty the deal looks from the outset, you might wonder how tempting it could possibly be – but Plummer says she can completely understand the thinking behind her character's choice.

"I mean, I remember the first time I walked onto set – Jon Henson, the art director, and everybody involved with bringing it to life did such an incredible, fantastic job," she says. "It was my favourite set to film in and the way that my character described it as like a fortress – somewhere she felt safe – that's actually how I as an actor on set felt.

"So yeah, I think had it been me in that situation... I mean, if you want a new start, I get it. Like, why not do it in this incredible house? So I think her decisions are relatable yeah, whether or not they're the right decisions to make."

Plummer says that she initially found the idea of acting in a show like this rather daunting, especially coming from the more familiar world of ongoing drama, and she admits that she cried on the way to set on her first day. But it didn't take her long to acclimatise, and she explains that working alongside actors such as David Oyelowo was a thoroughly rewarding experience.

"We shot it in Bristol, and I remember that the first week I was there, it was like, 'Oh my god, this is probably how I felt when I was on my first day of school,'" she says. "The whole casting was done over Zoom, so I hadn't actually met anybody face to face until we were in the thick of it. So it's very, very daunting for sure.

"In EastEnders, although you might be on different teams, you know everybody, so it's familiar. And as much as that familiarity with everybody is comforting and assuring, being on something like this with brand new people, it's just another opportunity to learn new things. I find it really interesting to meet... not necessarily actors, but you know – we became such a family from the camera department to the make-up department. It just felt like we were all small parts of a puzzle that connected made the most beautiful picture and yeah, it didn't take long before I felt really comfortable with everybody."

Although Plummer is going from one rather heavy role to another, she did find time to do something completely different in between – competing in last year's series of I'm A Celebrity... Get Me Out of Here! When we speak, it's right in the middle of the show's 2021 run, and Plummer tells me she's still in a group chat with last year's line-up, which has been "popping off all the time". She's not, however, been tempted to watch her own series back yet.

"I find it really difficult to watch," she says. "Giovanna [Fletcher] got it all recorded onto a hard drive and sent it to me last year as a present. So one day, when I've got grandchildren, we can sit down and I can show them about that one time I ate a goat's penis!"

Speaking of finding it difficult to watch things, Plummer says that although she can't wait for her family to see The Girl Before, they definitely won't be watching in the same room as her. "I don't think we can," she says. "I mean, my family really struggled when I played Chantelle, so I'm not sure. We were sent snippets of it before that I tried to show my mum and she was like, 'No, no no, I'll wait and I'll watch it with the world.' So yeah, I probably won't be watching it with them, but I will definitely be watching it and they will definitely be watching it."

As for what's next, Plummer says there are a couple of different things she'd like to try – like playing around in different genres and styles. "I would absolutely love to do something action-based," she says. "I would love to do a comedy. But yeah, it would be fun to do something where I can do my own stance and throw myself about and run – you know, have to do three months' training before I start the job. I would love to do something like that.

"For me right now, though, I feel like I'm transitioning coming from an ongoing drama to something like The Girl Before. So I just feel like I'm looking forward to this coming out and making that transition."

Read more:

• The Girl Before review: A pressure cooker drama with standout lead performances
• Meet the cast of BBC One thriller The Girl Before
• The Girl Before ending explained: What happened to Emma and Jane?

The Girl Before premieres on BBC One and BBC iPlayer at 9pm on Sunday 19th December 2021. While you’re waiting, take a look at our other Drama coverage, or find out what else is on with our TV guide.

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