(Cover) - EN Showbiz - Tilda Swinton felt at ease with her harrowing new role as she could "imagine [herself] as the mother of a scary son".

The Oscar-winning actress plays the mother of a teenage boy who embarks on a killing spree in the big screen adaptation of the bestselling novel We Need to Talk About Kevin. Tilda, who has 13-year-old twins, used her experience of motherhood to help prepare for the part.

"I have to feel compassion. And I have to be able to imagine myself in the situation," she explained to W magazine. "I can imagine myself as the mother of a scary son who looks at you with hatred. It's not about liking the person, but it is about understanding. The Greeks speak about the violence of the real. I want to get at something real.

"When I first saw the twins, I really liked them. And, at the same time, there was a ghost over my shoulder saying, 'What if I hadn't liked them?' Kevin spoke to that feeling. It is that nightmare scenario: What if you don't feel that connection to your children?"

The film, which wowed critics at Cannes International Film Festival earlier this year, is close to Tilda's heart, and she admitted she was desperate to star in the movie because "it scared me, and that interested me". She understands that most women worry about how they will react to becoming a mom.

"It's every pregnant woman's nightmare to give birth to the devil," she added. "And every mother worries that she won't connect to her children. When I had my children, my manager asked me what project I wanted to work on next. I said, 'Something Greek,' Nobody quite understood what I meant, what I was feeling." (C) Cover Media