(CNN) After spending $250 million to secure the rights to produce a "Lord of the Rings" television series, Amazon is doubling down on the world J.R.R. Tolkien created.

Amazon Game Studios is producing a free-to-play massively multiplayer online or MMO game based on Tolkien's novel. An MMO is an online game in which a large base of players cooperate or compete with one another in a vast, persistent open world.

The game is being developed in collaboration with Hong Kong-based Leyou Technologies Holdings Ltd., which produced the popular free-to-play "Warframe" game.

Athlon Games, owned by Leyou, originally announced the project last year with an unnamed partner, which was just revealed to be Amazon Game Studios.

No release date has been set for the game, which is being developed separately from the Amazon Original TV series.

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