LONDON, March 7 (UPI) -- Actress Maggie Smith has not signed up for the expected fourth season of the beloved British period drama "Downton Abbey," The Mirror reported. Production on the third season of the show is under way.

The series has been a huge ratings hit in the United Kingdom on ITV and in the United States on PBS. Set in the early 20th century, the drama follows the lives of the wealthy Grantham family and the many people who keep their great house running. Smith, 77, plays the sharp-tongued matriarch dowager countess of Grantham. 

The Mirror said Smith has alarmed the show's producers by not signing a contract for the anticipated fourth and fifth seasons of "Downton Abbey," even though the show has not been officially renewed that far in advance. 

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