Sigourney Weaver, Felicity Jones and Liam Neeson are among the cast
Published in 2011, A Monster Calls was written by Patrick Ness, based on an original idea by Siobhan Dowd, and illustrated by Jim Kay.
It tells the story of a young boy who has to face the reality of his mother suffering from terminal cancer, and a creature that visits him at night to help him deal with the pain.
Dowd suffered from terminal cancer herself when she started the story and died before she could write it.
For the big screen adaptation, Ness has written the script himself, and it is directed by Juan Antonio Bayona (The Impossible, The Orphanage).
Newcomer Lewis MacDougall will play the young boy, and will be surrounded by an all-star cast, with Liam Neeson playing The Monster, Felicity Jones as the boy's mother, Sigourney Weaver as his grandmother, and Toby Kebbell as his father.
The film is due for release in Irish cinemas from October 21st.