Spoiler alert: This interview contains spoilers from the first season of “The Crown.” Do not read until you’ve watched the full season. 

“I’m very proud of it,” says Claire Foy (“Wolf Hall”) of her role as Queen Elizabeth in “The Crown,” Netflix’s new series charting the rise of the young monarch.

And with good reason: Her performance in the drama, which debuts Nov. 4, has won critical acclaim, with Variety’s Maureen Ryan calling out the depth and specificity of her characterization, as she charts the moral center at the heart of creator Peter Morgan’s series.

Foy tells Variety she credits Morgan’s famously well-researched scripts, but also that she did her own extensive homework, finding her way into the character through her voice, as well as the support of her castmates, notably Matt Smith (Prince Philip) and John Lithgow (Winston Churchill).

Why did you want to play Queen Elizabeth?

It wasn’t so much her as the story in general. I felt like it was the entire family that I found really interesting and the death of her father was like a bomb going off in this family. None of them knew how to deal with it. It just so happens they were the most famous family in the world. And she suddenly had the most important job in the world. But I found she’s very challenging as a person for me to play because we’re not massively similar — vocally, physically, and she’s very in a control, stoic person. Or at least she seems to be. And I’m all over the show. So it was a real challenge as well. That’s what I thought would be brilliant about it. I would have to get involved and go the whole way.

How did you prepare?

I did loads of research, as much as I could do. I had lots and lots of help from production, with a voice coach and watched lots of footage. The researchers were amazing. The voice was a good way into it. It wasn’t so much her voice but the voice of the time. It was so different from how we speak now. That was key to get my head around. I love watching the old family videos of them in private life. It’s very difficult. There’s not a lot of firsthand accounts of her that you can say are definitely absolutely true. It’s quite difficult to get information about her, and there’s a reason for that. The rest of it, I relied on Peter Morgan, really, and went with what was in the scripts.

What surprised you the most from what you learned?

I think my preconceptions of her… As soon as I read the scripts I think the idea of her being a remote figure, a disembodied figure were gone, really. She’s like everybody else. It just so happens she’s not able to express herself in the same ways. She’s got her hands tied. Her duty and her job means that she’s not able to be open in the way that we all take for granted. The things that surprised me the most was how important her marriage and family were to her. And therefore how difficult it was for that to be a conflict in her life. They were the most important things to her, and all of a sudden for that to be the biggest problem was a complete nightmare. For her to be having problems between what she has to do, which she’s never not going to do, she’s such a duty-bound person, but then there’s her relationship to the people that she loves, which are the things she has to sacrifice, which is an awful position to be put in, really.

It all happened to her at such a young age, given her father’s death when she was just 25.

That’s the time when you should be allowed to be sad and not be ashamed of it. and be allowed to grieve and behave badly and come to terms with what happens. And she couldn’t do anything of those things. And it ricocheted across the whole family. It affected [her sister] Margaret and the Queen Mother and Philip. We see what the death means. It means that someone else has to step up to the plate. It’s immediate. There’s no glory in it. There’s no joy in it. It’s a nightmare. I don’t think she has ever has a chance or has the time to come to terms with it. Her religion comes in and helps a bit. There’s so many things asked of her and so much responsibility I don’t think she even began to carve out a time to sit in a room and come to terms with what she’s feeling.

And then her brand-new marriage gets tested, as her husband gets asked to walk two steps behind her.

I don’t think the kind of man she married was the kind of man who would do that willingly. It wasn’t that sort of relationship. That wasn’t the base of their marriage. All of a sudden the rules completely changed. And I don’t think he quite understands that she finds it even tougher. I think she’d much it rather it be the other way around.

How did you build your chemistry with Matt Smith, who played Prince Philip?

We just got on from the beginning. He’s such a lovely person and a brilliant actor. We both were quite open and (though) Oh God, how are we going to do this. We shared in the fear. He’s so lovely. Such a laugh on the set. I’m so lucky that we get to do it again.

You also had fantastic scenes with John Lithgow, who played Winston Churchill. Describe your relationship with him on set.

I love him. I can’t think of a single person who could have played that part apart from him. He’s just amazing. He’s got such humor and humility. He’s lived his life. And has a natural authority that I don’t think he knows he’s got. He’s an amazing person and a brilliant actor. It was so lovely to be around a person who enjoyed what he was doing and relishing it. and not too reverential. And I think that’s what that part needs. Otherwise it could have been an English actor paying homage to Churchill. John brought something different to it. It was amazing.

I never realized how much the young Queen didn’t know, how much Churchill had to teach her.

I never saw the play “The Audience.” I wish I had. But I know that Helen [Mirren] did some of those scenes. [Elizabeth] hadn’t been seen before like that. She was learning the ropes. She was so vulnerable and unprepared for the task. You always presume the people know exactly what they’re doing. It’s nice to see someone unsure and floundering a bit.

What was the hardest part of playing Elizabeth?

Just filming for eight months was quite hard. It was just challenging. Adjusting to what you thought you knew and realizing that’s not quite the case. Not going with the obvious. Not trying to be clichéd. Not take the simplest choice. Being brave. And trust that you’re doing it truthfully.

Was there one physical trick that helped you get into the part?

She plays with her hands and her wedding ring quite a lot. Which is quite telling. She’s not massively gesticulatory. I tried to remember that she’s far more solid and connected to the earth than I am.

Talk about Peter Morgan’s scripts. How did they help you?

They’re amazing. Everything ends upon the screen, to be honest. He’s just a genius. I don’t know how anyone can write such an arc of a story. I don’t know how you’d have the mental capacity to do it. It’s such a privilege to act out his scenes. They’re always surprising, really. You think you understand it and then you play it and it wasn’t that at all. It’s the sign of an extraordinary writer.

You’re about to start filming season 2. What lessons have you learned from the first season that you’ll bring to the season season?

Get more sleep. Take more vitamins. Keep my energy levels up. Trust peter’s scripts. And not be afraid to take the braver choice. And be the bad guy and tell the story as honestly as possible.