The new cast members will include Tom Cullen as Lord Gillingham, an old Crawley family friend, Nigel Harman as a visiting valet and Dame Harriet Walters as Lady Shackleton, a friend of the Dowager, The Hollywood Reporter said.
Dame Kiri Te Kanawa will be playing a singing house guest, Joanna David will guest star as the Duchess of Yeovil and Julian Ovenden will star as the aristocrat Charles Blake, The Reporter said.
"'Downton Abbey' has seen many great characters visit the house over the years and we couldn't be more thrilled to welcome the new faces that will be joining the regular cast of Downton in series 4," Downton executive producer Gareth Neame said Saturday in a statement. "We hope audiences will be as excited about them as we are."
"Downton Abbey" is produced by NBC Universal's Carnival Films has has won two Emmys, two Golden Golbes and a Screen Actors Guild award.