Jesse Eisenberg

Character: Simon James / James Simon

Mia Wasikowska

Character: Hannah

Wallace Shawn

Character: Mr. Papadopoulos

Yasmin Paige

Character: Melanie

Noah Taylor

Character: Harris

James Fox

Character: The Colonel

Cathy Moriarty

Character: Kiki

Phyllis Somerville

Character: Simon's Mother

Gabrielle Downey

Character: Strange Woman

Jon Korkes

Character: Detective

Craig Roberts

Character: Young Detective

Kobna Holdbrook-Smith

Character: Guard / Doctor

Susan Blommaert

Character: Liz

Bruce Byron

Character: Skinhead

J. Mascis

Character: Janitor

Tony Rohr

Character: Rudolph

Karima Riachy

Character: Secretary

Tim Key

Character: Care Worker

Andrew Gruen

Character: Man on Train

Kim Noble

Character: Box Man / Guard 1

Morrison Thomas

Character: Coughing Man

Sally Hawkins

Character: Receptionist at Ball

Lloyd Woolf

Character: Investigator

Lydia Fox

Character: Well-Dressed Woman at Ball / Test Invigilator

Stuart Silver

Character: Waiter / 'The Replicator' - Guard 2

Chris Morris

Character: Workers' Services Executive

Chris O'Dowd

Character: Nurse

Donal Cox

Character: Priest

Kierston Wareing

Character: James' Funeral Date

Paddy Considine

Character: 'The Replicator' - Jack

Dirk Van Der Gert

Character: 'The Replicator' - Head Judge

Liam Bewley

Character: 'The Replicator' - Wise Judge

Gemma Chan

Character: 'The Replicator' - Glamourous Judge

Nathalie Cox

Character: 'The Replicator' - Jack's Wife

Daniel Chapple

Character: Executive Worker (uncredited)

Martin Crossingham

Character: Paramedic (uncredited)

Danny

Character: Singer (uncredited)

Catherine Delaloye

Character: Air Hostess (uncredited)

Lukas DiSparrow

Character: Resident (uncredited)

Joanna Finata

Character: Bar Girl (uncredited)

Jeanie Gold

Character: Waitress (uncredited)

Steve Saunders

Character: Moaning Man on Trolley (uncredited)

Rade Šerbedžija

Character: Frightening Old Man (uncredited)

Natalia Warner

Character: The Girl (uncredited)