Zac Efron

Character: Richard Samuels

Christian McKay

Character: Orson Welles

Claire Danes

Character: Sonja Jones

Ben Chaplin

Character: George Coulouris

Zoe Kazan

Character: Gretta Alder

Eddie Marsan

Character: John Houseman

Kelly Reilly

Character: Muriel Brassler

James Tupper

Character: Joseph Cotten

Leo Bill

Character: Norman Lloyd

Patrick Kennedy

Character: Grover Burgess

Aidan McArdle

Character: Martin Gabel

Al Weaver

Character: Sam Leve

Thomas Arnold

Character: George Duthie

Megan Maczko

Character: Evelyn Allen

Jo McInnes

Character: Jeannie Rosenthal

Iain McKee

Character: Vakhtangov

Simon Nehan

Character: Joe Holland

Travis Oliver

Character: John Hoyt

Simon Lee Phillips

Character: Walter Ash

Daniel Tuite

Character: William Mowry

Imogen Poots

Character: Lorelei Lathrop

Saskia Reeves

Character: Barbara Luddy

Shane James Bordas

Character: Conspirator

Alessandro Giuggioli

Character: Conspirator

Harry Macqueen

Character: Conspirator

Rhodri Orders

Character: Conspirator

Michael J. McEvoy

Character: Epstein

Garrick Hagon

Character: Dr. Mewling

Aaron Brown

Character: Longchamps Kid #1

Emily Allen

Character: Virginia Welles

David Garbutt

Character: Mercury French Horn Player

Jay Irving

Character: Mercury Percussion Player

Steven Parry

Character: Mercury Trumpet Player

Marlene Sidaway

Character: Grandmother Samuels

Robert Wilfort

Character: Radio Director

Michael Brandon

Character: Les Tremayne

Nathan Osgood

Character: Radio Announcer

Janie Dee

Character: Mrs. Samuels

Eddi Reader

Character: Singer

Jools Holland

Character: Band Leader

Gilson Lavis

Character: Drummer

Dave Swift

Character: Double Bass

Mark Flanagan

Character: Guitar

Fayyaz Virji

Character: Trombone

Michael Rose

Character: Tenor Sax

Phil Veacock

Character: Alto Sax & Clarinet

Nick Lunt

Character: Baritone Sax

Jason McDermid

Character: Trumpet

John Young

Character: Longchamps Kid #2

Greg Bennett

Character: Hobo

Cris Blanco

Character: Museum Patron (uncredited)

Lexie Lambert

Character: Lizzy (uncredited)

John Patten

Character: Theatre Owner (uncredited)

Chris Wilson

Character: Studion Foley Artist (uncredited)