Credit: Steffan Hill/MASTERPIECE/PBS

Actress Ruth Wilson (The Affair) never met her grandfather, Alec Wilson, but he’d always been “a man of mystery” to her family: He secretly married multiple women, including Ruth‘s grandmother, Alison, but none knew of his polygamy until after he died.

In Mrs. Wilson, a miniseries based on Alison’s private memoirs, Iain Glen (Game of Thrones) plays Alec, while Ruth plays Alison. “It took an awful lot out of me,” she admits. “The life she constructed is pulled from underneath her…. It was an enormous responsibility and an extraordinary experience that was, in the end, quite spiritual.”

Besides, Alec wasn’t a complete cad. “He was adored by Ruth‘s family,” Glen says. “He created the problem in the first place, but nonetheless…” The mystery runs deep — and in this chat with EW below, Ruth dives deeper into what it was like tackling her family story.

ENTERTAINMENT WEEKLY: How much of the story did you know growing up?
It wasn’t until I was in my late teens that I found out one part of the story. My grandmother wrote the memoir in two parts, and the first part was about growing up and meeting Alec, and then discovering on his death bed that there was another wife.

She only wrote about one wife, and we speculate that she knew about more. Until after she’d died, we didn’t find out about the other two. So growing up, I didn’t know anything about my grandfather, and he was never spoken about. There’s no pictures of him, and my grandmother never talked of him, my dad never spoke of him. That was normal, that I had three grandparents and that was it.

And then everything came out. As the story got bigger, it became more curious and intriguing. I was so removed from it. As an actress I was just fascinated by what was inside of my own family. I think for my dad and for other members of the family, it was quite overwhelming in some ways to discover this… It’s been kind of an odd intrigue in our family that still feels quite removed [for me], because I’ve never met him. There’s an air of absence around him. He’s a construct of people’s memories.

Then, as an actress, when did you realize you wanted to tell your grandmother’s story, and to play her yourself?
The family kept growing, and the story kept growing, and every time I would see [my extended family], everyone would be like, “God, this is such a fascinating story.” And it wasn’t an immediate desire to do it at all. It was just, as I told more people outside of the family, everyone was like “Oh my God, you should make this into a drama.”

The more people I told, the more people start telling you their story of their family intrigue, and you realize that this would touch a nerve about secrets and lies within a family. I felt that was a really universal appeal. I suppose my name, my work was getting recognized elsewhere, so I wanted to put something on, in making this a reality.

Then me playing it, well… it felt like that was just the most obvious way to go, that I’d end up doing it through my grandmother’s eyes. I felt the only way I could protect her was by playing her in some way.

How much pressure did you feel playing her?
Enormous amounts of pressure. One, to get the story right and make sure all of the families that are talked about and dramatized are served, and [two], to try to get to the heart of the truth and see my grandmother. She was someone who turned to God — there’s not a lot of people that have that experience in their life, so who is the person that happens to?

Mrs WilsonPictured: RUTH WILSON, IAIN GLEN
Credit: Steffan Hill/MASTERPIECE/PBS

After making this series, did you walk away with a new understanding of your grandfather? Do you consider him guilty?
I don’t know. It’s interesting because I just found him fascinating. I just thought, “Wow, what a cad.” Everyone’s response are, “Oh my God, how’d he have four wives? What a legend.” I’m like, “Who is this man?” By the end, I’m in awe of my grandmother and the women. They were the breadwinners. They had to make enormously hard decisions in a time when women weren’t given the choice. I came out with such respect for them.

I probably have less respect for my grandfather. He created such chaos. But he’s not here to defend himself, and I think that what’s really important in the show was that all of the kids, my dad and my uncle and my new uncles, they all have such fond memories of their father. They were really insistent that was put in there, that this man, he had these women and these kids all loved him. There must have been something about him that was genuine.

Speaking of your new uncles, you’ve been in touch with your extended family. What has that been like?
That’s the most positive thing that’s come out of this, that we all found each other. We’ve had numerous [family] events. We first met 10, 12 years ago and biannually we try and get everyone together. We did a family screening [of the series], actually. It was the most incredible experience. There was silence afterwards as everyone took in what they just watched and were crying and hugging. This is the legacy of this man, this enormous family. The beauty of it is it’s solved questions in people’s own origins.

It must be nice to have some type of closure.
Yeah, and it’s funny because we don’t have closure on who he is. And life is like that, we are not sure we’ll ever find out those answers. Maybe we are not supposed to, maybe it’s okay not to. What we do have is this wider family.

Mrs. Wilson debuts Sunday, March 31 on PBS Masterpiece. Check local listings for times.

Related content: