Fans of Phillip Reeve's Mortal Engines novels were quite thrilled back in October, when it was revealed that Universal Pictures and Media Rights Capital are teaming up with Peter Jackson to bring this adaptation to the big screen. Today we have word that the first cast members have come aboard, with Robbie Sheehan and Ronan Raftery signing on. No details about which characters they're playing have been revealed, but Robbie Sheehan is playing a lead character, while Ronan Raftery is playing a supporting role.

Variety broke the news on this casting, while also revealing that Universal and MRC are hoping to start production this spring, in Peter Jackson's home country of New Zealand, and that a December 14, 2018 release date has been set. As of now, no other movies are slated for release on that date, but Sony has set up their untitled Spider-Man animated film one week later on December 21, 2018. 20th Century Fox has also set a Christmas 2018 date for Avatar 2, but there have been rumors it may be delayed once again.

Peter Jackson and Frank Walsh have been involved with this project from the beginning, optioning the rights to Phillip Reeve's novel series from Scholastic way back in 2001. A report surfaced in 2009 that he was "secretly" developing an adaptation of the novels, but we didn't hear anything further about this project until last year, when Universal and MRC came aboard to produce and finance the film, which Universal will distribute globally. Peter Jackson will not be taking the helm, though, with Christian Rivers, who has worked as a visual effects supervisor for Peter Jackson's Weta Digital, set to make his feature directorial debut.

Related: Why the Heck Are Minions in Peter Jackson's Mortal Engines?

First published in 2001 by Scholastic, Phillip Reeve's Mortal Engines books have won several prestigious awards including the Guardian Children's Fiction Prize, the Los Angeles Times Book Award, the Smarties Gold Award and Blue Peter Book of the Year. Mortal Engines is set in a world many thousands of years in the future. Earth's cities now roam the globe on huge wheels, devouring each other in a struggle for ever diminishing resources. On one of these massive Traction Cities, Tom Natsworthy has an unexpected encounter with a mysterious young woman from the Outlands who will change the course of his life forever.

Peter Jackson, Fran Walsh and Philippa Boyens, who co-wrote both The Lord of the Rings and Hobbit trilogies, are all writing the screenplay adaptation for Mortal Engines. Peter Jackson and Fran Walsh will produce alongside Zane Weiner, Amanda Walker and Deborah Forte, with Ken Kamins, the longtime manager for the writing trio, executive producing, and Philippa Boyens serving as co-producer. Robbie Sheehan currently stars in the UK TV series Fortitude, and he is no stranger to fantasy adaptation, portraying Simon in the 2013 fantasy adaptation The Mortal Instruments: City of Bones. Ronan Raftery most recently played Langdon Shaw in the Harry Potter spin-off Fantastic Beasts and Where to Find Them.