Upon entering the studio of William Ivey Long, who designed the costumes for The Belle of Amherst, a play about Emily Dickinson that begins previews today, the first thing __Joely Richardson__saw was a huge picture of her late sister, Natasha Richardson, as Sally Bowles. “And it’s so funny, because there she is, sexy as hell in this black lace corset, and a jaunty cap, and tons of makeup,” Richardson said over dinner last week. “And I thought, Wow, that’s Tash, and I’m going in for my Emily Dickinson little white dress. These are very different endeavors.”

It turned out that Long had designed the costumes for that 1998 Broadway revival of Cabaret, for which Natasha, who passed away in 2009, won a Tony award. “People think that that’s a sad thing,” Richardson added. “But you know, that’s lovely to me, to see her there, to know how brilliant she was, and how she struggled with that role and was terrified of it.”

Richardson says that like her sister was then, she is now completely outside her comfort zone playing the 19th-century poet in The Belle of Amherst—a one-woman play. “I’ve never attempted such a thing. I never thought that I would,” she said. “I mean, I would have said to you definitively, any time up until the last few months, ‘Oh God, I’m not going to do that. Not my bag. Only crazy people would do that. That is my absolute idea of hell.’”

She did see Bette Midler’s 2013 one-woman show, I’ll Eat You Last. “I remember sitting in the audience, thinking, She is bloody fantastic. I love her. How the hell did she have the guts to do that?” Richardson had also seen Fiona Shaw’sThe Testament of Mary, as well as her mother, Vanessa Redgrave, in The Year of Magical Thinking. “Each time, I thought: Amazing, but not for me. Way too scary,” she said, laughing. (Redgrave told Richardson, when she took on the Dickinson project, that “there will be moments of utter terror.”)

But once she read the play, she accepted the role immediately. “The thing is, it’s very rare to be offered such beautiful work, and if you are lucky enough for it to come your way, and you say no, because that’s too scary, too challenging, what does that say about you?”

Not much is known about Dickinson’s personality, so Richardson is not trying to re-create her, but interpret her. “She is wildly complex, and also wildly contradictory; even her poems contradict themselves.” The role is taxing. “Sometimes it’s very academic, other times it’s wildly emotional, other times it’s deep, hopefully, to the point of emotions equivalent to being stabbed,” she said, and laughed. “That’s what she talks of [in her poems], so it’s trying to bring that to life.”

“The other thing that I love about her in the play is how mischievous she is, very sardonic, very naughty, irreverent; not at all earnest, or pious, or worthy.”

And despite taking on Emily Dickinson, and being part of a family of theater royalty, Richardson likes to mix it up. She had roles in the television series Nip/Tuckand The Tudors, was in David Fincher’sThe Girl with the Dragon Tattoo, did Chekhov opposite Ethan Hawke Off Broadway, and recently shot a zombie movie, Maggie, with Arnold Schwarzenegger.

When we met for dinner, Richardson was still in the rehearsal stage. “I went to Amherst, I started to read [Dickinson’s] letters, and the poetry, and then I started to work on the play. I’ve seen documentaries, I’ve talked about her with people who are Emily Dickinson scholars,” she said.

To try to nail Dickinson’s accent, Richardson looked up Julie Harris’s Tony-winning 1976 performance in the same role. “I watched about five minutes. And I’m glad I did, because what a beautiful voice, what a beautiful everything she had. And then I thought, Oh my God, I have to stop listening to this right now! Right this second. And I switched it off,” she laughed.

Just before she was to begin rehearsals, Richardson found, in a family album, a card that Harris had written to her grandmother, who was also an actress. “I discovered it by accident,” she said. “And it was so funny to think that I had a personal item of Julie Harris’s in my flat.”

The Belle of Amherstwill play Off Broadway at the Westside Theater for a limited engagement.