'Very scary indeed'

He added that there was a lot of himself in all three characters - Susan, Tony and Edward. Susan "with her lack of self-confidence", Tony and Edward who are sensitive rather than dominant.

"They do not possess the stereotypical traits of masculinity that our culture often expects, yet in the end they both triumph. As a boy growing up in Texas, I was anything but what was considered classically masculine.

"Many things from my own life have worked their way into the screenplay for the film, just as details from Susan and Edward's life together seeped into Edward's story," he adds.

Adams manages to make troubled Susan sympathetic, something she found difficult: "it was a tricky one to prepare because when I first started exploring Susan, I didn't like her, and I can't play a character I don't like."

For his part, family-man Aaron Taylor-Johnson, 26, says he did a lot of research for his role, including extensive reading on American serial killer, kidnapper, rapist, and necrophile Ted Bundy.

The result, Ford admits, is "scary, very scary indeed".