Actress Olivia Cooke's future couldn't be brighter, as she swaps horror for indie films

You can't make a film out of tragicomic novel without the perfect, terminally ill final third character in that title. The film's director, Alfonso Gomez-Rejon, cast about and found someone in a genre that both he and she are well-versed in - horror.

"It's a very expressive genre," says Gomez-Rejon, who directed episodes of TV's and the film . He found his "Dying Girl" on TV's . But young Briton Olivia Cooke's resume includes the British horror thriller , as well as and supernatural thriller . Gomez-Rejon saw talent and a kindred spirit in 21-year-old Cooke.

"Horror has allowed both of us an opportunity to show what you can do," he says. "This film let us both show something deeper. She had to be someone who could be funny without trying to be funny. She's confident, like Rachel, her character … She commands her scenes, and handles even the toughest emotional moments with such grace."

Cooke, whose character is diagnosed with terminal cancer and is reluctantly befriended by two high school filmmaker/classmates, chose to shave her head for her chemo scenes. But when your first leading lady role had you crazy, dishevelled, in various states of self-injured undress in , shaving your head's nothing, right?

"I don't think horror taught me much of anything," Cooke says with a laugh, noting how was the one great experience she's had with the genre. "I never went to drama school. I'm winging it, doing my own thing. So maybe I 'went to school' in those films. Horror certainly taught me to be patient, and to appreciate a really good script and the chance to do something that proves I can do other things."

Cooke's close enough to her teens that she respected the characters in Jesse Andrews' script (he also wrote the novel it's based on). "These movies are too often conceived by 50-year-old men writing in their swanky apartments in Burbank. They make girls like this riddled with insecurities and self-deprecation. The girls never seem to like themselves. I was a girl who liked myself."