Keira Knightley as Georgiana Cavendish, Duchess of Devonshire

Ralph Fiennes as Duke of Devonshire

Charlotte Rampling as Lady Spencer

Dominic Cooper as Charles Grey

Hayley Atwell as Bess Foster

Simon McBurney as Charles Fox

Aidan McArdle as Richard Brinsley Sheridan

John Shrapnel as General Grey

Alistair Petrie as Heaton

Patrick Godfrey as Dr. Neville

Michael Medwin as Speechmaker

Justin Edwards as Macaroni

Richard McCabe as Sir James Hare

Calvin A. Dean as Devonshire House Servant (as Calvin Dean)

Hannah Stokely as Devonshire House Maid

Andrew Armour as Burleigh

Emily Jewell as Nanny

Bruce Mackinnon as Sir Peter Teazle

Georgia King as Lady Teazle

Luke Norris as Footman

Eva Hrela as Charlotte (Age 3)

Poppy Wigglesworth as Charlotte (Age 9)

Emily Cohen as Harryo

Mercy Fiennes Tiffin as Little G

Sebastian Applewhite as Augustus

Angus McEwan as Lord Robert

Kate Burdette as Lady Harriet

Laura Stevely as Lady Elizabeth

Benjamin Noble as Lord Ambrose (as Ben Garlick)

Max Bennett as Lord Walter

Camilla Arfwedson as Lady Charlotte

Fiona Sheehan as Young Girl in Theatre

Sarah Wyatt as Servant Girl

Thomas Arnold as Dealer

Gilbert Wynne as Althorpe Servant

Richard Curzon as Heaton's Clerk

Sophia Johnston as Guest at Lady Melbourne's Ball

Katerina Tana as Guest at Lady Melbourne's Ball

Clive Pearse as Narrator (voice)