Alex Lawther

as Vlass Mikhailich

as Elijah

as Leonard

as Joe DiMaggio Hermit

as Velveteen Rabbit (voice)

as Bastien

as Karis Nemik (voice)

as Abacus Woodlouse (voice)

as Karis Nemik (archive footage) (uncredited)

as Laurence

as Morisot

as King Charles VI

as Shaman

as Jack

as Theo

as Philip Wittebane (voice)

as Alex Goodman

as Alex Morin

as Mildred's Friend / Additional Voices (voice)

as Mildred's Friend (voice)

as Amberson

as Simon Rifkind

as Billy Bloom

as Tibby Schlegel

as James

as Christopher Robin Milne (Teen)

as Volunteer: Joey

as self

as Sam Sipowitz

as Elliot

as Rory

as Young Alan Turing

as Isaac Cooper

as Benjamin Britten

as Kenny

as The Boy

as Fred Bamber

as Sam Trabucco