The runaway hit novel by Paula Hawkins, "The Girl on the Train," has been optioned for film, and now the cast is starting to fill out. According to Deadline, the title role and lead character for the film, which narrates the story in the book, has been cast with Haley Bennett playing the lead role.

The story revolves around a woman named Rachel (Bennett), who makes a morning commute every day on a train that passes a certain house. In the house, she imagines the characters she sees everyday with a backstory that she creatively narrates for the lives she envisions them leading.

The lives are those of the man and woman who seem to be a perfectly happy couple that ignites her imagination, and she becomes obsessed, in her own mind, with what their stories are. She creates the story for them.

But one day on a commute, she sees something shocking happen at the house, and this of course leads her to seek them out, away from the safety of her train and into the all-encompassing nature of their real-life stories that she really knows nothing about.

The story also unfolds with two other women, which will be played onscreen by Emily Blunt and Rebecca Ferguson. The book carefully plays out with thrilling intrigue as all three women become deeply involved in the plot that takes place outside the train, and outside Rachel's fantasy world.

It has been likened to the film "Gone Girl," which was also a shocking hit with fans of the literature world. Both novels will now have a film presence, and the trend for adapting novels into movies continues to be a steady draw in the industry.

The casting process now continues with filling out the male roles in the film, which have not been announced yet. There has been no word yet on when production will start or when a possible release date is for the film.