The streaming service confirmed in a tweet Thursday it acquired rights to the movie, which is based on the Thomas Savage novel of the same name.
The Power of the Dog is directed by The Piano helmer Jane Campion. The project marks Campion's first feature film since Bright Star, which premiered at the Cannes Film Festival in May 2009.
"We are so excited to bring The Power of the Dog, Jane Campion's first feature film in over a decade, to Netflix and select theaters in 2021," the post reads.
The Power of the Dog centers on a pair of wealthy brothers, Phil (Cumberbatch) and George Burbank, joint owners of the biggest ranch in the Montana valley. George secretly marries local widow Rose (Moss), upending his life with Phil, who attempts to destroy Rose.
Deadline reported Campion, Emile Sherman, Iain Canning, Roger Frappier and Tanya Seghatchian will produce the film, with Rose Garnett, Simon Gillis and John Woodward as executive producers.
Cumberbatch most recently played Doctor Strange in Avengers: Endgame and will reprise the character in Doctor Strange 2. Moss portrays Offred on The Handmaid's Tale, which will return for a third season June 5 on Hulu.