The move will enable film fans to watch the forthcoming sci-fi epic Dune and the Matrix sequel on HBO Max at the same time as their cinema release.
Typically, new releases are shown exclusively at cinemas for months.
But with many cinemas shut due to the virus, studio revenues have plunged.
As a result, Warner Bros said all of its 2021 releases would go straight to HBO Max, the streaming service owned by its ultimate parent company AT&T.
The films will be available on the service, which is not yet available in the UK, for one month after release.
The releases are expected to include Godzilla vs Kong, Mortal Kombat and The Suicide Squad.
Warner Bros had already announced that its big budget Christmas action movie - Wonder Woman 1984 - would be available on HBO Max, as well as in cinemas.
Ann Sarnoff, chair and chief executive of WarnerMedia Studios, said the pandemic called for "creative solutions".
"No one wants films back on the big screen more than we do," she said.
"We know new content is the lifeblood of theatrical exhibition, but we have to balance this with the reality that most theatres in the US will likely operate at reduced capacity throughout 2021."