Keira Knightley was left a nervous wreck on the set of new movie a Dangerous Method when she plastered her trailer with grotesque and disturbing images of humans in turmoil.

The British actress plays mental patient-turned-psychoanalyst Sabina Spielrein in the upcoming drama, and she put herself through extreme preparations for the role.

I hated it. And now I'm scarred for ever

She decided to surround herself with pictures of distorted and screaming humans from the work of famed artist Francis Bacon - and admits it was a deliberate move to unnerve herself as she's been terrified of Bacon's images since she was a child.

Knightley tells Culture magazine, "Honestly, it was terrifying. I covered my entire trailer on set with these pictures, which were so animalistic, almost demonic, especially the studies for the Crucifixion.

"My mum took me to an exhibition of his work when I was really little and I just remember how claustrophobic and completely terrified I was.

"I hated it. And now I'm scarred for ever".

But the Pirates of the Caribbean star is adamant being surrounded by Bacon's most disturbing images helped her perfect her role, adding, "(It worked) because for me the work depicts madness.

And I always think of Francis Bacon when I think about someone who is in that sort of place".