As Variety said, it's no surprise that the film took so long to get made, because it's "a double whammy by industry standards: it's headlined by two women, who fall in love with each other."

Attached to the project for several years, Blanchett began to wonder if the movie would ever get made. "It was so hard," she says. "Midrange films with women at the center are tricky to finance. There are a lot of people laboring under the misapprehension that people don't want to see them, which isn't true."

Cate Blanchett on the set of CarolCate Blanchett on the set of Carol

When asked if this was her first lesbian experience, Blanchett notoriously replied, teasingly, "On film, or in real life?" She then added that she had relationships with women "many times", later qualifying her answer to say that they weren't sexual relationships. And when asked how she addressed this theme in the performance, she said, "I never thought about it. And I don't think Carol thought about it either. But in 2015, the point should be: who cares? Call me old fashioned but I thought one's job as an actor was not to present one's boring, small, microscopic universe but to make a psychological connection to another character's experiences. My own life is of no interest to anyone else. Or maybe it is. But I certainly have no interest in putting my own thoughts and opinions out there."

To prepare for the role, Blanchett read some vintage fiction and spent time talking with the film's costume designer, Sandy Powell. "We asked, 'What is the most erotic part of the body?'" Blanchett recalls. "We kept saying that wrists are really erotic. The neck. The ankles. The way Highsmith writes, she's got this exquisite observation of detail that most people would miss, but a lover's eye never would. We talked a lot about erogenous zones."

But ultimately the key came in understanding the subtle differences between today's culture and the more repressive experience of living in the early 1950s. Blanchett says that the main difference is that Carol's sexuality is private. "What often happens these days is if you are homosexual you have to talk about it constantly," she says. "But Carol's sexuality isn't politicised. I think there are a lot of people that exist like that who don't feel the need to shout things from the rafters."

Watch the trailer for Carol here: