James Corden as Paul Potts

Alexandra Roach as Julz

Julie Walters as Yvonne

Colm Meaney as Roland Potts

Jemima Rooper as Hydrangea

Mackenzie Crook as Braddon

Trystan Gravelle as Matthew

Sion Tudor Owen as Choirmaster

Alex MacQueen as Dr. Thorpe

Miriam Lucia as Signora Fiorentino

Stanley Townsend as Luciano Pavarotti

Di Botcher as Nurse

Jon Wennington as Talent Show Punter (uncredited)