Gillian Anderson stars in BBC Two's new psychological crime thriller The Fall. As Detective Superintendent Stella Gibson, she is brought in from the Metropolitan Police by the Police Service of Northern Ireland to review a stalled murder investigation.

What compelled you to take the role of DSI Stella Gibson?
She feels a little like an island but I find that interesting and it makes me want to know more, which is always a good thing where character and drama is concerned.

Can you tell us a detail from the script where you felt a connection to Stella?
It's hard to say. I am intrigued by her no-nonsense way of being. And that over time we get to see warmth and what she cares about. She is an enigma.

What are the key factors behind Stella's professional decisions?
I think she is professional and driven and has a mind for this kind of work and knows that if she keeps at it she will crack it. I think on the whole she works from instinct but I think this case touches her much deeper and that's in part what is driving her. Her emotions have become engaged and that's unusual for her. She is thrown.

Are her personal decisions driven by different impulses? Such as when she introduces herself to the policeman...
Obviously this is one of the ways she compartmentalises for better or worse. She has found a way to justify this act in her mind. She is used to dominating her environment and here she goes again. I think we all have to compartmentalise, especially with all the versions of ourselves we are expected to perform with some self- and society-imposed perfection. We do it with aspects of our inner selves and with relationships between work and home and other.

How do you portray this contrast?
It's compelling to see characters that have duality. Playing that is easy. It feels more natural for one, than a single dimensional character but also there's layers to build on and that's the joy and challenge of the work. Humans are more complex than our wildest imaginations. And then sometimes, oftentimes, we as individuals can't even explain why we do the things we do. We take stabs at it, we hypothesise and justify, but then years later we may realise it was all down to a forgotten event in childhood. So any fabricated history for a character can also have that same complexity – the character might even think it's one thing but it can be something laying much deeper.

Do you think there are any aspects of her character that she shares with Paul Spector?
Yes but I think I need to let that unravel on screen.

Gillian Anderson plays DSI Stella Gibson in The Fall.

The Fall starts at 9pm on Monday, 13 May on BBC Two and BBC Two HD. For further programme times please see the episode guide.