Shirley MacLaine will be returning to Downton Abbey next season as Martha Levinson and six new cast members will be joining the show as well, Carnival Films and Masterpiece on PBS announced this morning. Opera star Dame Kiri Te Kanawa is joining the cast as a guest who sings in the house, as confirmed last night among three other new cast members including Tom Cullen who will play Lord Gillingham, an old family friend of the Crawleys who visits as a guest for a house party. Plus Dame Harriet Walter arrives as Lady Shackleton, an old friend of the Dowager played by Maggie Smith and Julien Ovendon comes aboard as aristocrat Charles Blake. Additions revealed in this morning’s announcement were Nigel Harman who joins the household as Green, a valet, and Joanne David who has a guest role as the Duchess of Yeovil. Downton Abbey is a Carnival/Masterpiece Co-production, created and written by Julian Fellowes. Gareth Neame and Fellowes are exec producers.