Sex and the City actress Cynthia Nixon isn't the first person you'd think of if you were making a biopic about the death-obsessed 19th century poet Emily Dickinson. And indeed, Nixon admits that it's "definitely, absolutely" the most challenging part she's played.

Cynthia Nixon in A Quiet PassionCynthia Nixon in A Quiet Passion

She says it wasn't easy "depicting someone who at times is so full of love and excitement about the world, but also has such deep emotional and physical pain." Never married, Dickinson died at age 55 after a long struggle with kidney disease. The majority of her poems were published after her death.

To play the role, Nixon had to combine the external composure and internal turmoil. "She's completely ferocious," she says. "She has an enormous amount of delicacy and artistry, but the fact of the matter is she's just blunt. Her poetry is like that too: so direct, even for now. She rejects being ornamental. She rejects it as a woman and she rejects it as a writer. She wrote so specifically from her vantage point and she didn't compromise anything. I always think of something that Quentin Crisp said: even if society views you as a pariah, an outcast, a freak, wallflower, whatever, if you stand your ground and remain true to yourself, society will come to see, in time, what you were talking about."

Playing this "bundle of contradictions" was a great challenge, Nixon says, especially in her later years. "The last part of the film is where I really connected with her as a person," she says. "The torment of love and unrequited love, or unfulfilled love at least. I'm in my fifties now, and the truth is the older you get, the more death you see. But you know, it's a juicy thing for an actor to get to do: a death scene!"

And Nixon feels that Dickinson's story is important today. "I think whatever she would've done," she says, "whatever field and era she would've found herself in, she would've succeeded. I do think she would've found an audience more readily had she lived now. I think she would be astonished to see how not just famous she is, but how important she is to writers and readers all over the world."

Playing Dickinson reminded Nixon how things have improved. "I'm very lucky to be living exactly right now," she says, "because I think we have more focus on women's stories. Also there's just more female everything! More female producers and writers and directors and actresses of a certain age who create vehicles for themselves."

Watch the trailer for A Quiet Passion: