Winona Ryder became "obsessed" with the 'Heathers' script when she landed a role in the cult classic movie.

Winona Ryder

Winona Ryder

According to the film's producer Denise Di Novi, the now 47-year-old actress simply loved the plot for the 1989 dark high school comedy and insisted on playing the role of Veronica Sawyer in the picture despite her agent advising her against it.

In an interview with Variety marking the movie's 30th anniversary, Di Novi said: "Winona Ryder is so smart, very brave and unusual. She was this amazing 15 year old, if you can believe it. Winona got obsessed with the script."

The movie follows Veronica as she joins a high school clique of popular girls all named Heather (Kim Walker, Lisanne Falk and Shannen Doherty), however, she starts to question the bullying behaviour.

However, when bad boy student J.D. (Christian Slater) joins the school, Veronica becomes obsessed with him and he tricks her into killing the clique's leader Heather Chandler (Kim Walker).

Veronica then learns that J.D. is out to kill everybody he doesn't like and even plans to blow up the school.

The film's screenwriter Daniel Waters believes the movie's long-term appeal is that the story lulls viewers into a false sense of security and even the title sequence song 'Que Sera Sera' - which was re-recorded by Syd Straw as Doris Day wanted nothing to do with the movie due to its foul language and nudity - makes audiences believe they're watching a film with a "nice message at the end".

He said: "The whole thing about 'Heathers' was lulling you into thinking you're watching a different movie. [The song] makes them think they're watching a film about girls, a film about teenagers, rebels and bullies and it's going to have a nice message at the end. Then you slap everybody in the face in the middle and mess with their minds."