Cast rounds on eOne drone warfare thriller, which also stars Colin Firth.

Helen Mirren and Aaron Paul have joined Colin Firth in drones warfare thriller Eye in the Sky.

Mirren will star as Colonel Michelle Madden, a military intelligence officer in command of a top secret drone operation.

Paul takes the focal role of American drone pilot Steve Watts.

As previously announced Firth, who is also attached as part of an ensemble cast, and Ged Doherty of their Raindog Films outfit will produce the film alongside Xavier Marchand who will oversee production for eOne.

Gavin Hood will direct Guy Hibbert’s script. Shoot is due for September in South Africa.

eOne International is shopping the film in Cannes.