Lily Collins has been cast as Lord of the Rings writer J.R.R. Tolkien's wife in a new biopic.

The Mortal Instruments: City of Bones star will play Edith Bratt, who was the inspiration behind the elven princess characters in the Lord of the Rings franchise, according to Variety.com. Lily will star opposite Nicholas Hoult, who will play Tolkien.

Finnish filmmaker Dome Karukoski is directing the biopic, which will center upon the turbulent times that inspired Tolkien to pen The Lord of the Rings and The Hobbit.

A timeline for the film has yet to be announced.

This isn't the only Tolkien project in the works - filmmaker James Strong is also directing a movie about the writer, titled Middle Earth.