Keira Knightley has revealed she relished the challenge of playing a villain in her new movie Never Let Me Go - the opening film at the 2010 London Film Festival.
The 25-year-old Hollywood beauty stars opposite rising British stars Carey Mulligan and Andrew Garfield in the film adaptation of Kazuo Ishiguro's novel, which sees their characters entwined in a love triangle, born out of Keira's character's jealousy.
Keira, used to playing the heroine, said of playing the story's villain: "It was great."
She added: "I saw that the character was fascinating - for me it was kind of a study of jealousy and fear. She commits great harm and I thought it was interesting trying to get into her head.
"I didn't like her and it's tricky playing people that you don't like and finding a way to empathise with them. And that's challenging and very exciting."
Co-stars Andrew and Carey revealed they were not weighed down by the emotional subject material of the film, in which they play clones, bred purely for the purpose of becoming organ donors.
The Social Network's Andrew confessed: "It's easier to cry than to make people laugh."
An Education star Carey agreed: "It's always harder to maintain raw enthusiasm or joy than to go into a really dark place.
She added: "This for us really was about trying not to cry. I cry all the time, it's my modus operandi."
Never Let Me Go, directed by One Hour Photo's Mark Romanek from a screenplay by Alex Garland will open the BFI London Film Festival at the Odeon Leicester Square tonight.