As Daenerys Targaryen in HBO’s “Game of Thrones,” the British actress Emilia Clarke battles evil while armed with dragons and an apparent immunity to fire. But as Louisa Clark in “Me before you,” she’s a mere mortal caring for a demonically angry Englishman (Sam Claflin) determined to end his life after being hit by a motorcycle and paralyzed. At which point Lou decides to help him live again.

It’s a role Ms. Clarke was determined to play the moment she received the Jojo Moves novel from which Thea Sharrock’s romantic drama, opening on June 3, was adapted. “I was utterly convinced that someone had found me and written me, Emilia, down,” she said. “It wasn’t even a question that I would do whatever it took to be able to play Lou.”

That included chemistry reads with six men before she and Mr. Claflin (“The Hunger Games”) were partnered, “which was wonderful because we already knew each other,” she said. “We sort of cheated.”

In a phone interview, the Emmy-nominated, Berkshire-reared Ms. Clarke, 29, a Drama Center London grad who had but two tiny parts on her professional résumé when she was cast as Daenerys, spoke about her love of the sea, warrior women and unlikely namesakes. These are edited excerpts from the conversation.

Why are you calling from California?

I spend half my time in London, half my time in Los Angeles. But sometimes L.A. can feel a bit intense and soul sucking. When you’re by the sea, you’ve got that sea air blowing all of the anxiety cobwebs away from every person who’s desperate to make it. The people walk around with no shoes on and surf, and I feel like I’m on holiday every day.

Do you surf?

No, no, no, no, no. I like watching pretty boys surf, but I don’t surf. Many boyfriends have tried to get me on surfboards, but it’s just not attractive. It’s not 90210. It’s 911.

How is Louisa like you?

Where we meet Lou is very much where you would have met me when I was 15 and younger. Her naïveté and simplicity are what bring the comedy to play, because it’s done in this really open, innocent way in terms of her choices and how she lives her life. You see a girl growing up and discovering the things that will change her fundamentally, and that’s lovely to watch.

Assisted suicide is a sensitive topic for many people. How do you feel about it?

Well, I am very English and very liberal. So I believe that everybody in life should be able to have a choice, regardless of the subject. And I think that’s the thing we’re talking about in this movie.