Keira Knightley

Georgiana Cavendish, Duchess of Devonshire

Ralph Fiennes

Duke of Devonshire

Charlotte Rampling

Lady Spencer

Dominic Cooper

Charles Grey

Hayley Atwell

Bess Foster

Simon McBurney

Charles Fox

Aidan McArdle

Richard Brinsley Sheridan

John Shrapnel

General Grey

Alistair Petrie

Heaton

Patrick Godfrey

Dr. Neville

Michael Medwin

Speechmaker

Justin Edwards

Macaroni

Richard McCabe

Sir James Hare

Calvin A. Dean

Devonshire House Servant (as Calvin Dean)

Hannah Stokely

Devonshire House Maid

Andrew Armour

Burleigh

Emily Jewell

Nanny

Bruce Mackinnon

Sir Peter Teazle

Georgia King

Lady Teazle

Luke Norris

Footman

Eva Hrela

Charlotte (Age 3)

Poppy Wigglesworth

Charlotte (Age 9)

Emily Cohen

Harryo

Mercy Fiennes Tiffin

Little G

Sebastian Applewhite

Augustus

Angus McEwan

Lord Robert

Kate Burdette

Lady Harriet

Laura Stevely

Lady Elizabeth

Benjamin Noble

Lord Ambrose (as Ben Garlick)

Max Bennett

Lord Walter

Camilla Arfwedson

Lady Charlotte

Fiona Sheehan

Young Girl in Theatre

Sarah Wyatt

Servant Girl

Thomas Arnold

Dealer

Gilbert Wynne

Althorpe Servant

Richard Curzon

Heaton's Clerk

Sophia Johnston

Guest at Lady Melbourne's Ball

Katerina Tana

Guest at Lady Melbourne's Ball

Clive Pearse

Narrator (voice)