The Crown's Erin Doherty on her happy place and getting inside people's minds

Erin Doherty stars in the acclaimed psychological thriller Chloe, streaming now on Amazon Prime Video

There's one room that is my happy place. It's a rehearsal room at the top of the Old Vic Theatre in London. It's the most beautiful room I've ever been in. The roof is just glass. There's something really inspiring about rehearsing a play and talking about creative things while seeing the blue sky - or, the rainy sky let's be honest, it is in London. But there's something about feeling so connected to those elements whilst you're creating something.

It's just my happy place. If ever I'm down I just take myself back to that rehearsal room. The people that have stood on those wooden floorboards and had discussions about character, maybe for hours, that for me is when my theatre geek truly comes alive. I love thinking about that.

I feel like Judi Dench surely was up there, she's done stuff at the Old Vic. That's mental for me. I love it! I'm someone who wants to know exactly what's in someone's mind at any given moment. I would've loved to have been a fly-on-the-wall for a Judi Dench play. I just want to know her process. What is she fascinated by? What does she struggle with?

I genuinely love the struggle. I want to play people that are really confusing, that on any given day you're like, 'I just can't connect to why she's doing these things'. That's great to me. Finding the character should be a struggle because people are so complex. I feel that in order to give them the respect that they deserve it should take you a lot of time and graft.

I never feel, 'oh cool, yep, I've got them'. That never happens. For me, it's about time. I want at least a month with someone trying to figure out who they are on my own before I go into a rehearsal room or before I'll step on a set. I want, selfishly, to sit with them for a month. To understand and genuinely put things into place and the events that happened in their life that got them from A to B I need some time alone. Only once I've done that, can I bring them into a rehearsal room and offer them up.

Erin Doherty as Princess Anne in the Netflix royal drama, The Crown.

Theatre has been a part of my life for so long. Mum and Dad put me and my sister into drama lessons on the weekends when I was four or five. So the theatre feels like home. There's something I've always found really homely about it. There's something about everyone being in a room together and deciding to tell this story or watch this story that is really comforting. I find it a really hopeful place to be. It gives me a lot of faith in humanity that we still want to pay some money and go hear people tell a story. How lucky that I get to be a part of that.

When I'm on stage it's like the world drops away. It's not like time stands still. There is no time. There is no world. You're there, completely committed to telling this story. There's an immediacy to it that's irreplaceable. I will never let go of theatre. It's magical. Nothing else exists when you're doing it.

For me, being an actor gives you greater patience with people. People are complex and on one day they may give you an answer and on another, they may tell you the opposite. That is part of being a human being. You can't expect people to show up every day in the same way. That's why we're fascinating. That's why we're animals. That's why we're so brilliant. There's something really beautiful about going, 'okay I'm going to sit with this version of you today and that's okay and tomorrow you can give me someone completely different and I've got time for that person too'.

I don't think we're 2D. We're so multidimensional and each day those parts fascinate me. That's why I jumped at Chloe. There's something that happens when you know as an actor that you want to be a part of something because you stop reading a script and become that person and start seeing it through their lens. I wasn't reading it, I was in it, literally seeing through her eyes.

The Crown was such a huge, huge thing to be a part of. Even before I got there. That was the scariest thing, being accepted into that family as it were, on the back of the success of Claire Foy and Matt Smith. That was terrifying.

The Crown was also my first big gig so I feel like I spent my childhood there growing. When it finished I was like a teenager ready to go out on my own and now I'm out in the big wide world I'm gonna see what happens. There's something really, really nerve-wracking about that but also really freeing.

* As told to Karl Puschmann. Erin Doherty stars in the psychological thriller Chloe, streaming now on Amazon Prime Video.