Royle Family actress Sue Johnston is joining the cast of ITV's Downton Abbey, in a guest role. Johnston will play Denker, a lady's maid to Dame Maggie Smith's character, the Dowager Countess of Grantham.

Sue JohnstonSue Johnston Is Joining Downton Abbey

Johnston, best known for playing Barbara on The Royle Family, joins fellow guest stars Richard E Grant and Anne Chancellor - both of whom will play guests of the Granthams at Downton.  

Series four of the show achieved an average of 11.9 million viewers in the UK and the show returns to screens this autumn. The British drama has also been a success in the US, winning both Emmy and Golden Globe awards. Over 26 million viewers watched season four, making it one of the highest rated shows on American television. 

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Previous stars to guest on the series include Shirley Maclaine, who played Martha Levinson, and the Oscar-nominated actor Paul Giamatti, who appeared in last year's Chirstmas special as Levinson's "maverick, playboy" son. 

Series five will also feature Rade Sherbedgia, the actor best known for '24' who will play a Russian refugee who has fled the revolution after World War I.

According to the BBC, executive producer Gareth Neame promised it would have "all the usual highs and lows, romance, drama and comedy."

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