Domhnall Gleeson as A. A. Milne

Will Tilston as Christopher Robin Milne

Alex Lawther as Older Christopher Robin Milne

Margot Robbie as Daphne Milne

Kelly Macdonald as Olive

Nico Mirallegro as Cooper

Stephen Campbell Moore as Ernest

Phoebe Waller-Bridge as Mary Brown

Geraldine Somerville as Lady O

Richard McCabe as Rupert

Shaun Dingwall as Alfred

Vicki Pepperdine as Betty

Simon Williams as Zoo Director

Bentley Kalu as American Cop

Mossie Smith as Sharon the Midwife

Stanley Hamlin as Christopher Robin Aged 6 Months

Dexter Hyman as Christopher Robin Aged 3 Years

Sonny Hyman as Christopher Robin Aged 3 Years

Sam Barnes as The Times Photographer

Allegra Marland as Fan 1

Mark Tandy as Portrait Photographer

Richard Dixon as MC at Pageant

Ann Thwaite as Pageant Dignitary

Nicholas Richardson as Newspaper Man

Kevin Millington as American Chap

Rolan Bell as American Cop

Mark McKerracher as Groupie 1

Amber Batty as Groupie 2

Grace Curtis as McGovern Sister

Matilda Curtis as McGovern Sister

Lance C. Fuller as Groupie 3

Simon Connolly as Radio Host

Richard Clifford as Toy Shop Manager

Cameron Lane as Kid 1

Phoebe Lyons as Kid 2

Harper Gray as Kid 3

Nick Blakeley as Zoo Photographer

Victoria Bavister as Mother at Zoo

Robert Portal as Headmaster

Tommy Rodger as Douglas Minor

Vincent Finch as Big Boy

Jim Cartwright as Military Medic

Beatrice Stein as Dancer

Sarah Jayne Butler as Winning Mum