Suggestions by @bigdaddycaster

Andy Serkis

as Peeves in Harry Potter

Stephen Fry

as Slughorn in Harry Potter

Eric Cowell

as Goyle in Harry Potter

Tristan Ruggeri

as Crabbe in Harry Potter

Keira Chansa

as Romilda Vane in Harry Potter

Orson Matthews

as Oliver Wood in Harry Potter

Marli Siu

as Tonks in Harry Potter

Tom Hardy

as Fenrir in Harry Potter

Nicholas Hoult

as Barty jr in Harry Potter

Blake Harrison

as Peter P in Harry Potter

Tom Glynn-Carney

as Sirius in Harry Potter

Eleanor Tomlinson

as Lily P in Harry Potter

Josh O'Connor

as James P in Harry Potter

Siobhan Finneran

as Hooch in Harry Potter

Saoirse-Monica Jackson

as Trelawney in Harry Potter

Serrana Su-Ling Bliss

as Cho Chang in Harry Potter

Freya Skye

as Cho Chang in Harry Potter

Owen Cooper

as Cedric in Harry Potter

Dan Stevens

as Lucius in Harry Potter

Saoirse Ronan

as Narcissa in Harry Potter