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Harriet Slater

British actress Harriet Slater has found a home for herself on Pennyworth, but 2023 promises much more to come.

For Leicester native Harriet Slater, London was always calling. Growing up participating in local theater, the thought of attending drama school seemed only natural. Now, only a few years since graduating, she’s moved to the big city, steadily booking roles and ready to make her mark. Currently known for her portrayal of Sandra Onslow in DC’s Pennyworth, the next year promises to change that.  She has recently wrapped the next installment of the beloved Indiana Jones franchise, True Haunting, an adaptation of the novel by Edwin F. Becker, which also stars Jamie Campbell Bower and Erin Moriarty, and Horrorscope, another horror in which a group of college friends mysteriously begin dying after getting their horoscopes read. However, for Harriet, Sandra Onslow will always be special.

Season 3 of Pennyworth, which was released alongside a move to HBO Max, promised both larger audience numbers and a more intrinsic role for Harriet Slatter. As she has grown over the past three years, so has her character. Although for Sandra, the years passed have doubled.  A role that began as a simple love interest for the show’s titular character, fans have enjoyed watching her come into her own and develop into a well-rounded woman. A feat that Slater has given depth to, embodied, and learned from.

Harriet chats with 1883 Magazine’s Sydney Bolen about her time spent playing Sandra Onslow, her upcoming projects, her recent trip to Los Angeles, and more.


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I wanted to start by saying congrats on the third season of Pennyworth. I know a lot of fans are really excited that it got added to the HBO Max roster. That opened the show up to a whole new audience.

Yeah, it has.


You’ve portrayed Sandra Onslow for 3 seasons now. How does staying with a character for so long affect your performance or understanding of the role?

I think she’s changed a lot from season one. She started as a very young, naive barmaid who worked at Alfred’s local pub. The extent of her part used to be that she had a crush on him. Now, in season three, it feels as if she’s a completely different person. Her whole life has changed in the six years since season one. She’s got a great career as a lounge singer, which is a lot of fun, and has grown up a lot. It’s almost been like playing three different people, to be honest. You do feel like you know them a lot better than you would if you were to jump in and play a character for a day, but the other side of that is that you feel like you know the other characters a lot better as well. It’s nice. You establish relationships with the other characters. But, at the same time, Sandra has changed so much, so she still surprises me. She’s grown so much in her assertiveness and her sense of herself. She’s really learned to stand up for herself over the years, which is nice to see.


Is that your favourite way she’s changed over the years?

I think so, yeah. In season one, and especially season two, I understood why she was behaving the way she was and letting Alfie treat her badly, and obviously, I had to empathize with her, but at times in my head I was screaming, “just leave him! Run! Get the hell out!” You have to empathize and understand why they’re acting the way they are, and staying in that situation. It’s because she is completely in love with him. I think we’ve all been in situations where people treat us like shit, but we’re obsessed with them, so we put up with it. I was really happy to see that she finally learned to stand up for herself. She doesn’t take as much of his shit now as she has in the past. 


Because he played her for a while, do you think you’ve learned anything from her?

Honestly, I’m terrible at confrontation. I am the worst, truly. It’s the most annoying thing, but if I’m really really angry during an argument, I’ll generally just cry. Oh, my God.


Same. 100% me too.

Oh, my god.


And you’re like, “I’m not upset! I’m angry!”

Yeah! It’s the most frustrating thing. You can’t articulate anything because you’re completely overwhelmed. You can’t say what you want to say. Later you think back on all the things you wished you’d said, but at the moment, your mind just gets completely freaked out. Sandra has a couple of times in season three, where she goes at Alfie. She says everything that she needs to say. I found the way that she deals with confrontation inspiring. She channeled her anger and just let it all out. She told him exactly how she felt and exactly what she thought of him. That is something I wish I could do a little bit better.




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I wish I could do that as well. As we near the finale of season 3, what advice would you give her?

That’s a really good question. It sounds so cheesy, but I would tell her to keep pursuing what she wants, to focus on her own needs and desires, and not sacrifice that for anyone else.


Moving into 2023, you have some very exciting upcoming projects. One of which is True Haunting in which we will see you alongside Erin Moriarty and Jamie Campbell Bower. The film is based on the book by Erin Becker. Have you read it? 

Yeah! I read it while I was shooting actually. It’s quite short and it’s a really good read. I think it was more invested in it because like we were doing the film. I found it so interesting. I was very surprised by how similar it was to the film. Have you read it?


I haven’t. But I’ll probably read it before the film comes out. 

Well, I was shocked. Obviously, it is based on a true story. But I assumed the majority of the film script was artistic license. Some of it is, obviously, but the things that he and his wife experience, a lot of those are accurate. It’s mad to read. I fully believe in ghosts. [chuckles] That made the whole filming experience a little bit scary. I’d only been on set a couple of nights when I woke up in the middle of the night from a nightmare, sat bolt upright in bed, the full-on horror movie moment. I was like, “Oh my God, these are real ghosts that we’re dealing with. What if they know.”


For people that haven’t read the novel, what can you tell me about your character?

I play April Becker, who is the younger sister of Ed Becker, who is the guy that wrote the books. He’s played by Jamie in the films. It’s set in the early 70s, which was so much fun. My first experience with this film was the producer coming over to London to take me shopping for the character. They weren’t happy with her costumes in Serbia where we filmed. We went around to all the vintage and charity shops in Notting Hill and Covent Garden, piecing together the wardrobe for her. It was probably my favourite day. 


Did you get to keep anything? 

I didn’t keep anything.



I know, but a couple of the tops I wore in the film were actually my tops, so I guess I kind of kept something. [laughs] But back to April. She’s young, she’s a bit of a hippie. She doesn’t have a job. Her brother sees her as quite irresponsible because he’s married and has a baby. He’s older and at a different time in his life. April is torn between loving her lack of responsibility and wanting her brother to take her seriously. He basically raised her, so I think she feels indebted to him. They have a really nice relationship. I loved working with Jamie and Erin so much.


I’m excited to see it. I’m in a bit of a horror kick right now, which fits right into this interview because you’re filming a horror movie, Horrorscope, right now. How’s filming been?

I’ve been filming for four or five weeks. We’ve only got a few days left. At this point, it almost feels like sleepwalking because the majority of the film is set at night. We’ve been doing a lot of night shoots, which starts exciting, but then your body hits a certain point and it gets hard. It’s been hard, but it’s really fun. We’ve all bonded a little bit because everyone has just been so tired all the time.


Are you a fan of the genre yourself as you’ve been doing a lot of work in it?

I am. Yeah! I’ve never expected to do two horrors in one year. I love horror. My boyfriend and I watch horror movies all the time. He finds them terrifying, which is highly entertaining. I don’t generally find them scary unless they’re about something paranormal because then I’m genuinely like, “oh my god. This could be real.” Those do unnerve me, but generally, I just find them entertaining. 


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I am the same way. As long as the bad guy dies in the end, I’m good to go. You have one other huge project coming up: Indiana Jones! I know you can’t reveal much, but I read your interview with Wonderland Magazine where you talked about not knowing what you were auditioning for. You must have imagined something. What did you think the audition was for?

I genuinely had no idea. It’s a very small part. I don’t even know what I’m allowed to say. The NDA was insane. I’m only in one scene in the film. 


Ok, but It’s a scene in an Indiana Jones movie.

Yeah, exactly! My boyfriend lost his mind. He grew up watching the films. You’re right. It is insane. It’s a huge deal. I’m so happy to be even a teeny tiny part of it. I’m just praying they don’t cut the scene.


Oh, no. Now when I go see it, I’m going to be like, “Is Harriet here?”

It’s near the start of the film, so if you don’t see me early on, that’s a bad sign. I had to sign this crazy NDA to even have access to the one side I was given. I haven’t read any of the script besides that one page that had all the names changed, so I know nothing at all. [laughs]


With Wonderland, you also talked about growing up surrounded by theater. Are you hoping to get back to the stage on a bigger scale at some point?

Yes, totally. I love the stage. I miss it so much. I haven’t been on stage since early 2018. I did a play in Chester in the UK at Storyhouse. I’m so grateful that I have been doing so much TV and film work recently. I’m loving it. But, I would love to return to the stage soon. I feel so free on stage. Growing up, I did theater. At drama school, you mainly do stage work. It’s so exciting and terrifying at the same time. I miss being there with the audience. It’s so different from TV and film. Films don’t come out until about a year after you shoot, so you don’t get that immediate audience response. With theater, that response is different every night. I love them both for different reasons. But, I would love to return to the stage.


I hope this isn’t weird, but when I was stalking your Instagram to prep for this interview, I noticed your Beverly Hills photo dump included a picture of the cereal aisle at the grocery. I was curious as to why?

[laughs] When I went to LA there were so many things that I saw that I’d only ever seen on TV or in films my whole life. In the UK, we grow up watching American TV and films and we play in an American accent, so you feel quite connected to it. But in another way, it’s an entirely different world. The cereal was one of those things. You see it so much in media, cereals like Froot Loops, which we don’t have. That was e a moment of pure excitement. We were in the car and a yellow school bus went by. I literally screamed. Those are the kinds of things that I’d only seen on TV. Seeing them in real life was kind of insane.


Finally, to bring everything back to Pennyworth, the show is set in London in the 1960s. If you could go back there for one day, what would you do?

That’s the hardest question! Only for a day?


I’ll change it to a week.

Oh my god. Okay, a week I can do. I’d start up in Liverpool. I’d go watch The Beatles and Cilla Black. My dad grew up in Liverpool in the 60s, so I’d be interested to see what it was actually like. He’s told my sister and me so many stories about it, so I’d like to see it for myself and maybe go visit him as well and see what he was like as a little boy. Then, I’d travel on to Leicester, which is where I’m from, and my parents still live there now. My dad moved to Leicester in the 80s and he met my mum. I’d go see what my mum was like as a kid because she was growing up in the 60s as well. My grandpa had a chocolate factory in Leicester. 


That’s so cool!

I’d love to go see that in action because that closed down before I was born. I’d also like to see my grandparents when they were younger. You only ever know them as your grandparents. It’s kind of weird, but they had this whole life and were other people before you even existed. I’d love to see what they were like. Finally, I’d come down to London to go shopping on Carnaby Street. That would be my perfect week in the 60s.



Pennyworth is airing now on HBO Max.


Interview Sydney Bolen

Photography David Reiss

Styling Alton Hetariki

Make up Nadia Braz represented by Moja Management using So PR, Rude Cosmetics, ICI PARIS XLClay and Glow 

Hair Pashcan’el Mitchel represented by Moja Management using uberliss 


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