Brendan Gleeson also stars in the project, which received a straight-to-series order a month before Yelchin's death.

David E. Kelley's series adaptation of Mr. Mercedes is moving forward.

The forthcoming AT&T Audience Network drama has tapped Penny Dreadful grad Harry Treadaway to replace the late Anton Yelchin, The Hollywood Reporter has learned.

Mr. Mercedes, based on Stephen King's 2014 book of the same name, follows a demented killer who taunts a retired police detective with a series of lurid letters and emails, forcing the ex-cop to undertake a private, and potentially felonious, crusade to bring the killer to justice before he is able to strike again.

Treadaway will play Brady Hartsfield, a mentally deranged ice cream truck driver and IT worker who is secretly the Mercedes Killer. He will star opposite Brendan Gleeson, who will portray Detective Bill Hodges, a retired cop driven out of retirement when an old nemesis reappears.

The adaptation received a straight-to-series order in May with Yelchin and Gleeson attached. However, the Star Trek actor was tragically killed in a car accident the following month. He was 27 years old.

Kelley will serve as showrunner on the series, which is being produced by Sonar Entertainment. Jack Bender (Lost) is set to direct. The duo will executive produce with Temple Hill Entertainment's Marty Bowen and Wyck Godfrey. Mr. Mercedes is slated for a 2018 debut on DirecTV and AT&T U-verse.

Best known for playing Dr. Victor Frankenstein on the recently wrapped Showtime series Penny Dreadful, Treadaway has also appeared in The Lone Ranger and City of Ember. He is repped by ICM and Principal Entertainment LA.