Paul Giamatti joins the cast of Downton Abbey

The Golden Globe winning actor will play Cora's brother Harold, the rather free-spirited uncle of Mary and Edith.

“We can't wait to see him,” said Gareth Neame, Managing Director of Carnival Films, the production company behind the popular period drama.

Alongside returning star Shirely Maclaine, Paul is sure to stir up trouble in this year’s Christmas Day episode.

The fourth series, which will return to British screens this autumn, will follow Downton favourites, Dame Maggie Smith, Hugh Bonneville, Michelle Dockery and Jim Carter.

Other new additions to the cast include Dame Kiri Te Kanawa, Tom Cullen and Gary Carr, who plays the “charming and charismatic” jazz singer, Jack Ross.

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