Alicia Vikander and Michael Fassbender found it "easy" to fall in love.

And though they are notoriously private about their relationship, they're are currently in the middle of the press tour for the movie and when asked about their relationship, Alicia said: "I think we've made a clear statement that we keep certain things just between us. It was very easy to unite, but that's quite personal."

The Derek Cianfrance's directed title chronicles a couple falling for each other, and Michael insisted it wasn't the romance romantic setting of the movie that brought them together.

In an interview with Entertainment Weekly, Michael added: "It wasn't the first time in a movie either of us had played somebody who is falling in love. There is an element of separation there. If I'm playing a murderer, I don't go out and start murdering people."

The couple made their red-carpet debut at the Golden Globes in January and although they are happy to be photographed together, the Assassin's Creed star refuses to share more intimate details about their life.

The 39-year-old Irish-German star said: "I'm not going to talk about my private life with a total stranger, unless I feel like I need to.

Why would I? I don't."

Meanwhile, 27-year-old Alicia revealed she fell for Michael when they spent a month together in an isolated lighthouse on the set of 'The Light Between Oceans'.

The 'Danish Girl' star felt "terrified and very alone" when she first arrived but was immediately put at ease by him.

She shared: "He was very sweet at letting me in ... He was like, 'Can you please give me a note? What do you think I should do?' It was such a sweet thing to kind of let me in."