David Harbour has exited Behemoth!, the upcoming Searchlight Pictures film written and directed by Tony Gilroy. The move comes after production had already begun, with multiple outlets reporting that the project has moved forward with a replacement actor.
While the exact reason for Harbour’s departure has not been publicly detailed, coverage notes it happened after a period of filming and amid his commitments tied to the final season of Stranger Things.

What happened and what has been confirmed
Entertainment Weekly and Deadline report that Will Arnett has been cast to replace Harbour in Behemoth! and that the recasting is not expected to delay production.
People also reported the exit earlier this week, noting Harbour had recently filmed scenes and that the role was being recast following Variety’s initial report.
What Behemoth! is and who is involved
Behemoth! is described as a drama centered on a musician returning to Los Angeles, with the story tied closely to film music and the people who make it.
The cast includes Pedro Pascal and Olivia Wilde, along with Eva Victor, Matthew Lillard, Margarita Levieva, and Alexa Swinton, according to reporting on the film’s ensemble.
Tony Gilroy is best known for his work, including Michael Clayton and for his involvement in the Star Wars universe through Rogue One and Andor, and he is writing and directing this project.
When production started, and why “months into production” is accurate
Entertainment Weekly reports that Behemoth! began filming in October and that the production is continuing through the recast.
That timeline matters because it explains why the story is being framed as a mid-production shift rather than a routine casting change before cameras roll.
What Harbour is doing next
People notes Harbour remains linked to several upcoming projects, and his Stranger Things obligations have been a major part of his current schedule in recent months.
For now, neither Harbour nor the production has provided a detailed public explanation beyond what has been reported: he exited, the role was recast, and filming is expected to continue.

