The film will start shooting in November, right after Watts finishes filming on Michael Haneke's remake of his own psycho-drama Funny Games. Eastern Promises, written by Steve Knight, delves into the same seedy underside of London life that he explored in Dirty Pretty Things.
Watts will play Anna, a midwife at a London hospital who gets dragged into the criminal underworld when she tries to discover the identity of a dead patient.
Viggo Mortensen is set to play the mysterious and ruthless Nikolai, a man with links to one of London's most notorious organized crime families. His carefully maintained existence is thrown into turmoil when he crosses paths with Anna.