When drugs and alcohol are involved, it can be difficult to keep things straight.

Eve Hewsonlearned that lesson in nitty-gritty detail while making the new historical dramaThe Luminaries(premiering Sunday onStarz).

Her various states of intoxication got so complex that Hewson had to devise a tracking system.

The Luminaries

Anna Wetherell/Starz

ENTERTAINMENT WEEKLY: Had you read the book or were you familiar with Eleanor Catton before signing on?

EVE HEWSON:I’m ashamed to say that I wasn’t familiar with her work.

But I read the scripts.

I think I was jet-lagged or something.

It was just really stunning.

So many of my friends loved this book.

That made me excited, because everyone was really excited to see it.

Eleanor has pivoted somewhat from fiction to screenwriting, adapting this and last year’s adaptation ofEmma.

How much interplay did you get to have with her, and did she help you shape the role?

Yeah, she was really present.

Eleanor’s really cool.

She’s a very, very fun person, so I just enjoy her as a human.

But she was around for most of our prep.

I did like three or four weeks of rehearsal.

The script was evolving every now and then, so she was in and out of set.

She was just like, “You’ve got this.

You’re Anna, just do it.”

She didn’t really have any notes, which was very kind.

What appealed to you about Anna?

She’s very unknowable, and you don’t know where she’s coming from.

I don’t think you fully believe her story that she’s in New Zealand to dig for gold.

There’s some mystery to her.

She comes up against all these characters in the story, and they’re trying to make her something.

Setting is a character unto itself here.

Had you been to New Zealand before?

Can you talk about how that impacted your work?

I’ve never been to New Zealand.

I went off for six months.

I remember thinking, “Holy crap, this is going to be a journey.”

It ended up being a really beautiful, peaceful setting to do some really f—ed-up work.

Most of the guys had more time off, and they went and traveled.

I was just running around like a lunatic.

What was it like jumping back and forth between those poles?

You had your notecards, but was it particularly challenging or confusing?

But we shot it by location, so that helped.

It wasn’t like I had to be fresh-faced in the morning and then a dug addict at night.

It’s such a funny thing.

The whole story makes or breaks itself based on their meeting.

That is the kickoff point to them going on their journeys and then coming back to find each other.

So we were all nervous to get that right.

But we ended up becoming really good friends because we were hanging out on the weekends and whatever.

She is very much a woman bound by the limitations of her era.

Did you find threads in her story to women of today?

It’s so relevant.

She is quite a feminist character.

I really enjoyed playing her and feeling her pain and suffering, but then also fighting back.

Allowing love to take over and believing in hope is really important for women.

It’s an old trope that women have to consistently revisit.

It’s important to watch someone fight against that and then come out of it, strong.

This interview has been edited for length and clarity.