HBO is looking for a new director on its “Lewis & Clark” miniseries, which has shut down production in Canada.

Director John Curran, who co-wrote part of the mini, has exited the project, HBO confirmed. News of the shutdown and director switch was first reported by Deadline. “Lewis & Clark” stars Casey Affleck and Matthias Schoenaerts as the famed 19th century explorers who went on a remarkable three-year journey to map the western United States.

“Lewis & Clark,” which has been long in the works at HBO, has a glossy pedigree as a co-production of Tom Hanks’ Playtone banner, Brad Pitt’s Plan B Entertainment and National Geographic Studios.

Production on “Lewis & Clark” began in June in Alberta. The six-part miniseries is based on Stephen Ambrose’s 1997 book “Undaunted Courage: Meriwether Lewis, Thomas Jefferson, and the Opening of the American West.”

Also exiting the production is d.p. Rob Hardy. There’s no word yet on when filming will resume. HBO described the situation as “temporarily pausing production,” although it will undoubtedly take some time for a new helmer to prepare to step in.