Will Arnett Replacing David Harbour in ‘Behemoth!’

in Movie

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(Left) Will Arnett at the 83rd Annual Golden Globes®, airing live from the Beverly Hilton in Beverly Hills, California on Sunday, January 11, 2026 at 8 PM ET/5 PM PT, on CBS and streaming on Paramount+. Photo: Francis Specker/CBS ©2026 CBS Broadcasting, Inc. All Rights Reserved. (Right) David Harbour from ‘Thunderbolts’ at D23 Expo 2022.

Preview:

Will Arnett is joining Tony Gilroy’s drama ‘Behemoth!’
He replaces David Harbour, who left the film for personal reasons.
Olivia Wilde, Eva Victor and Matthew Lillard are also in the movie.

‘Andor’ creator Tony Gilroy has had to make a change to his new dramatic movie.

Following word that David Harbour has departed the cast of ‘Behemoth!’ for unknown reasons (though part of it might have been exhaustion following the mammoth ‘Stranger Things’ press tour), Deadline reports that Will Arnett (‘Is This Thing On?’) has quickly been brought in to replace him.

We don’t know what role Arnett will be playing in the film, though apparently the amount to be reshot is minimal and the movie is still expected to wrap its production in the coming weeks.

What’s the story of ‘Behemoth!’?

(L to R) Tony Gilroy and Diego Luna on the set of Lucasfilm's 'Andor', exclusively on Disney+. ©2022 Lucasfilm Ltd. & TM. All Rights Reserved.

The cast of ‘Behemoth!’ is already full of names, including Pedro Pascal, Olivia Wilde, Eva Victor, Matthew Lillard, Margarita Levieva and Alexa Swinton.

While both Pascal and Gilroy –– thanks to their work in the ‘Star Wars’ galaxy –– are used to secrecy, this one is wrapped in even further layers of mystery. But a few details have emerged.

Gilroy has said in the past that it’ll focus on a cellist who moves back to Los Angeles and decides to make music for movies. The film explores why he came back and why he went away, delivered in a nonlinear, music-driven structure.

The whole movie is told through music cues, which trigger flashbacks spanning the last 20 years.

Oscar Isaac had been attached to the main role, but his busy schedule meant that he recently had to drop out. Ironically, Pascal, who might be one of the other busiest actors on the planet, had free time.

What else is Will Arnett working on?

Will Arnett stars in 'Is This Thing On?' Photo by Searchlight Pictures/Jason McDonald/ Courtesy of Searchlight Pictures. © 2025 Searchlight Pictures All Rights Reserved.

Arnett has been drawing some awards buzz for his role in Bradley Cooper’s ‘Is This Thing On?’ though has so far not scored any trophies.

He has a small recurring role on ‘The Morning Show’ and variety of projects in development, including TV series ‘Fish Out of Water’ and ‘Temporary Humans.’

When will ‘Behemoth!’ be in theaters?

Searchlight hasn’t yet said when ‘Behemoth!’ will arrive on its release schedule; the switch between actors is not expected to impact the timing since what needed to be re-shot was relatively small.