The 1925 novel, she said, was the "most read, loved book in America."
"Daisy is described in such adoring terms. I found that really intimidating, because I had always played normal women and normal girls," she added. "Of course, everyone who ever read that book knows exactly how they see Daisy in their own minds."
She felt the same way with her latest role, portraying yet another celebrated literary female protagonist, the strong-willed, independent and willful Bathsheba Everdene for Danish director Thomas Vinterberg's "Far From the Madding Crowd," based on Thomas Hardy's 1874 novel.
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"You can't dive into every single person's imagination and pick out the qualities they see in the character," Mulligan said by phone from New York, where she's starring in the Broadway revival of David Hare's "Skylight." As an actress, the 29-year-old noted, "you have to go by your instincts," no matter how well known the character is.
In the romantic drama shot in England's picturesque West Country, often referred to as "Hardy country," Bathsheba is a young woman without means whose life and fortunes change when she inherits her uncle's farm. The fearless Bathsheba is determined to run the property, much to the shock of the local male farmers.
("Hunger Games" author Suzanne Collins was inspired to name her resourceful Katniss Everdeen after the self-assured Hardy heroine.)
Bathsheba is also pursued by three very different suitors — the loyal, handsome shepherd Gabriel Oak (Matthias Schoenaerts); the wealthy older neighbor William Boldwood (Michael Sheen), who becomes obsessed with her; and the magnetic and reckless army sergeant Frank Troy (Tom Sturridge).
The Oscar-nominated actress ("An Education") didn't watch John Schlesinger's 1967 film adaptation of "Far From the Madding Crowd," starring Julie Christie as Bathsheba, preferring to use the book as her guide to the story.
"I loved the character," she said. "What I loved so much was the first thing she does in the book is refuse an offer of marriage. I found that so refreshing. So often so many of these period dramas are about women trying to find men to fix their problems and sort of start their lives."
Bathsheba's early feminist leanings weren't the only unusual aspect of the story Mulligan admired. "I mostly associate costume dramas with people standing in stiff corsets in dark mahogany rooms and talking in low voices. This was going to be about people really living in the land and riding around on horses and facing real problems," she said of the film, which opens May 1.
Vinterberg ("The Hunt"), who had seen most of Mulligan's previous work, thought from the outset that "she was the right person for the part."
"She was the perfect combination of being very vulnerable and yet very strong and smart," he added. "I thought she could capture this very independent spirit, because it is somehow part of herself."
Mulligan, he noted, also had "faith in my work."
"She is a woman who read the book many, many times — more times than I had — and sort of carried it with her as a kind of witness to everything we did," he said.