Cult novel Cloud Atlas was once considered unfilmable. For some movie critics, it still is.

The adaptation of the philosophical book by Britain's David Mitchell premiered at the Toronto International Film Festival to sharply divided reviews, suggesting the complex storylines and ambitious plot structure did not always connect with audiences who had not read the novel.

With a budget that reportedly topped $100 million, and an all-star cast of Tom Hanks, Hugh Grant and Halle Berry playing multiple roles, the pressure is on for Cloud Atlas to be a box office hit. And with Hollywood awards season just around the corner, anticipation is running high.

Co-directed by Tom Tykwer of Run Lola Run fame, and the sibling team behind The Matrix Trilogy, Andy and Lana Wachowski, Cloud Atlas is made up of six narratives spanning from the 1840s to the present day to a post-apocalyptic future.

The century-hopping film explores how actions can have consequences in the past, present and future, and the notion that humanity cannot help but repeat itself.

While Mitchell's book tells six separate but linked stories in chronological order, moving from the past to future and then back again, the film intercuts the stories to drive home the link between the threads.

"When you read the book you see that there are very resonant themes in all six stories," co-director Lana Wachowski said of the adaptation process at a news conference on Sunday.

"Once we started seeing the resonant pieces of narrative and the pieces of narrative that seemed connected, we began sort of laying it out as if it was one big story and that was our goal."

The film is scheduled to be released in the US late October.

Reuters