Naomi Watts will join Viggo Mortensen for the London-based thriller Eastern Promises.

David Cronenberg will direct the script by Steven Knight, which delves into the same seedy underside of London life that Knight explored in Dirty Pretty Things.

Watts will play a midwife at a London hospital who gets dragged into the criminal underworld when she tries to discover the identity of a dead patient.

The movie will begin filming in November.