Rooney Mara and Cate Blanchett in Carol.Irish Voice

Rooney Mara had her first Oscar nomination in her mid-twenties. At 30 she’s sure to get another one for her bewitching work in Carol, the 1950s lesbian love affair drama in which she plays a young woman falling hard for the radiant Cate Blanchett. Cahir O'Doherty listens to Mara discuss the role that has become the most important of her career to date.

Rooney Mara, 30, simply lights up the screen in Carol, director Todd Haynes masterful new drama in which she plays a young woman who’s swept off her feet by the older and more experienced Cate Blanchett.

It’s a risky role for the young star because the film is set in the buttoned up era of Senator Joe McCarthy, and that means Mara’s character has to be buttoned up too, pretty much dictating a lower key performance style that’s stripped of any histrionics.

It’s a world apart from Mara’s punk rock debut in The Girl With the Dragon Tattoo, but her characters quiet inner fortitude in Carol, which opens Friday, probably comes easily enough to Mara herself, a descendant of not one but two of America’s most prominent and long-standing Irish sporting families.

Mara’s mother’s family founded the Pittsburgh Steelers and her father's family founded the New York Giants; and her own name is a tribute to her twin lineages.

Her Irish connections don’t stop with her family. In 2016 she will star in Sebastian Barry’s eagerly awaited Secret Scripture, directed by Jim Sheridan. She spent time in Ireland this year filming the role.

Born sporting royalty and now also Hollywood royalty, in person Mara is both confident and unexpectedly shy. While Blanchett swans into the Essex Hotel on Central Park West on Monday morning to promote the film looking every inch the Hollywood movie star, Mara quietly follows in her slipstream, content to let the ravishing Australian blond draw the paparazzi’s focus.

But if you think that Oscar winner Blanchett can steal every scene from the less experienced Mara in Carol, think again. It’s precisely because Mara remains so aloof that she becomes so mysterious.

On screen she’s so banked down that she’s bewitching. We want to know what’s going on with her, what she values, and if and when she’ll fall in love.

The first time we meet Mara’s character Therese she is awkward young shop girl working in a 1950s version of Saks Fifth Avenue, but as Carol unfolds she slowly begins to step into herself, becoming an Audrey Hepburnesque beauty by the film’s final reel.

Blanchett plays Carol, and her interest in Therese makes her more interesting to herself. Watching Mara slowly come out of her shell and begin to blossom by falling in love is one of the great joys of the film.

Because it’s the early 1950s this will never be a coming out story, of course. That fateful step simply comes at too high a price. So instead we watch as Therese grapples with her private feelings and their public consequences.

The danger they’re often in makes every word, every little gesture of affection, resonate with a breathtaking intensity. A hand gently placed on a shoulder, the aroma of Carol’s perfume, even a simple lunch date can become loaded with eroticism because we understand how much is being denied.

For this reason director Haynes often films Therese inside the square boxes of cab or apartment windows, suggesting these are all frames that she needs to break out of in order to be herself.

Carol also offers a near total immersion in the era in which it’s set. The film’s period detail is a marvel, but it’s not a back to the future version of the ‘50s filtered though the lens of 2015.

Instead the film was shot in Ohio where they found perfectly preserved department stores from the era that retain the atmosphere in which they were built, giving Carol an unusually convincing period feel.

But the homophobia of 1952 has far from died by 2015, as we learned in the early moments of the press conference to launch the film. A female critic raised her hand and asked the two leads this question: "What I loved so much about this film is the love story between the two of you didn’t feel like it was a homosexual love story, it felt very heterosexual."

Blanchett raises an eyebrow. “It felt normal?” she asks dryly.

“Yeah, exactly," says the critic. "Is it because of the times that we’re living in now? Is that why we don’t care any more?”

Cate Blanchett and Rooney Mara in Carol.

Cate Blanchett and Rooney Mara in Carol.

But why would you ask if you didn't care? Speaking for the first time, Mara fixes the critic with an ice cold death ray stare I would hate to be on the receiving end of and says this, "To me there is no difference, it’s a hard question to answer. To me one of the great things about the film is that it’s not political, it’s not a film with an agenda. We’re not preaching to the audience. So people are allowed to just watch it for what it is, which is a love story between two humans."

Love, the film reminds us, is instinct more than it’s calculation. But finding yourself in a love affair that defies convention will require some calculation, which both women set about in contrasting ways.

“Carol lives in a quiet hell because she’s not able to express herself fully, I guess from the way she was brought up,” says Blanchett.

“She was not in a loveless marriage with her husband, and when she’s confronted by Therese she realizes she has an enormous amount to lose. She has to strike an unhappy balance with her husband because of her love for her daughter, and she is risking it all.”

There is a beautiful line in the film where Carol describes Therese as being “flung out of space,” an unexpected arrival in her life that changes everything, makes everything better.

“But it also refers to her being in uncharted territory, as you do when you fall in love for the first time. You’re confronted with questions and sides of yourself. It’s territory that you’ve never been in before,” Blanchett adds.

All though the press conference and afterwards you can see there’s lighthouse intelligence at work in Mara’s expressions, but she is quite content to keep it under wraps. That unusual reserve plays directly into her role in the film because there too Mara is both surprisingly shy and also passionate under that placid surface.

Clearly Mara is someone who values her privacy and has no patience at all for any invasions of it, or for the kind of questions that fly in the face of her own values.

Asked if the story of Carol is just a classic case of the heart wanting what it wants, she’s gives a heartfelt one-word answer. “Yes,” she says, simply.

Then she leans back in her chair, clearly aware that the film already says everything that needs to be said better than anyone at the conference could. Carol is that rare thing after all, a perfectly executed, immensely stylish masterpiece that is so well made it leaves nothing left to say. It’s all been so well said already.