Alicia Vikander found it very difficult to learn a new accent for her movie The Light Between Oceans.

In the film, the Academy Award-winner plays Isabel Graysmark, a local young woman in western Australia, who falls in love with Tom, as played by Michael Fassbender, an ex-serviceman who is hired as the lighthouse keeper on the remote island of Janus Rock.

Alicia spent hours with a dialect coach perfecting how Isabel should sound in the romance drama, with it decided that she should adopt a mix of British and Australian sounds, given the post-World War I setting of the film.

And the Swedish star admits that taking up the unique accent was a daunting task.

"I was terrified each day trying to do any accent on this film," she told reporters at a London press conference. "We started with discussing if we should do an RP (Received Pronunciation) accent knowing that a lot of the Australia sounds came after the Second World War but when we met our dialect coach she said I think there’s a way of morphing in the beginning of what is now considered as Australian sounds.

"We tried to find that own voice in the same way that (this is set in) a fictional town in Australia... There was a lot of frustration going on."

The 28-year old has been starring in English-language projects for the past four years and has become used to tackling accents, from English and American to German for The Fifth Estate.

Although learning a specific dialect can be a challenge, Alicia shared that working on an accent can also help her get into character.

"It brings you back into character immediately. So when you find that voice, when I learned Isabel’s voice, there's an excitement in that, you can fast track into her really," she explained.

The Light Between Oceans is released in U.K. cinemas on 1 November (16).