'Mortal Instruments' prequel already planned

The film 'The Mortal Instruments: City of Bones', based on hit teen fiction written by Cassandra Clare has already had a prequel commissioned, despite the first instalment not even hitting screens until August.

Constantin Films are obviously so confident that they've announced that a film based on the spin-off series of books, 'Infernal Devices' is in development. Author Clare has hired Stephanie Sanditz - better known as an actress - to write the screenplay.

'Mortal Instruments' stars Lilly Collins and Robert Sheehan and its plot sets a race of angels known as 'Shadowhunters' against vampires known as 'Downworlders.'

The prequel, based on books 'Clockwork Angel', 'Clockwork Prince' and 'Clockwork Princes's is set in Victorian England and surrounds events that precede those in the 'Mortal Instruments' series.

Lily Collins, daughter of prog rock drummer Phil Collins, most recently starred in 2012's Snow White fantasy 'Mirror Mirror.'