Hugh Dancy plays the title role in “Adam,” the story of a man with Asperger Syndrome, a form of social dyslexia that is on the autism spectrum. As the movie begins, Adam’s father has just died and he must learn to function on his own. Rose Byrne plays Beth, his new neighbor, who finds Adam’s inability to say anything but the literal truth an appealing quality because of her own losses and disappointments.

Hugh, one thing that really struck me in your performance was your walk, which really communicated a lot about the character. How did that develop?

It was a less conscious process than you might imagine. I never walked in my apt seven different ways to try to develop the right one. It was more learning the ways in which people are and are not tactile, being aware of the feeling of certain clothing, observation, obviously, and instinct. The first scene we filmed was the first one in the movie, the scene at my father’s grave. I waited until the camera was rolling and then had to walk away.

I was also impressed with your American accent and way of speaking — very different from the American accent you did in “The Jane Austen Book Club.”

It was as much about figuring out the voice as the accent. What I worked on was the delivery and tonality that is fairly typical of that condition. Getting that right and getting the rhythms right is what really mattered.

Tell me about what made you want to do this film.

What drew me to it was the way the character was treated, as a character as a bunch of symptoms. He is not labeled, until a good third of the way into the film, so you get to know him before you hear what his diagnosis is.

I understand that you and your fiancee, Claire Danes, have now both played characters with Asperger Syndrome.

She plays Temple Grandin in an HBO biopic. I had already finished this film before she took the role, so we shared research and we discussed both characters with each other.

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Rose, Adam is such an unusual and fascinating character that it must have been a challenge to make Beth and her concerns carry as much weight in the story. How did you make that work?

Beth had a crappy relationship with guys and a father who was overbearing and larger than life. Adam was the antithesis of all the people she was exposed to. And it was important that the romance took a while. That helped to make her role in the story stronger.

I was very interested in the way Beth’s clothes helped to convey her character. How did you work with the costume designer to determine what would best tell her story?

We talked about it a lot. Alysia Raycraft designed the costumes and she jumped at the chance to be creative with Beth and a little eccentric with the clothing. Beth favors vintage clothing, second hand things. We are a little surprised when we see how wealthy her parents’ home is because her clothes and apartment show that she has eschewed her middleclass-ness. A lot of the clothes were mine. Prada heels weren’t in the budget!