Paul Giamatti, who most recently appeared in the movie Rock of Ages and the George Clooney-directed political drama film The Ides of March, will soon be seen on the small screen when he appears as an immediate family member of one of the lead characters in Masterpiece Theater/PBS series “Downton Abbey.”

TVLine reports that the actor has joined the cast of the British drama’s upcoming fourth season as Harold Levinson, “the maverick, playboy brother” of Cora Grantham played by Elizabeth McGovern. Giamatti will appear in the season’s finale along with Shirley MacLaine, who will return in her role as Cora and Harold’s mother.

A representative for Carnival Films, which co-produces the series revolving around an aristocratic family during the reign of King George V, expressed enthusiasm about the Sideways star’s new role.

“We’re excited that Paul Giamatti will be joining us on ‘Downton’ to play Cora’s brother Harold, the rather free-spirited uncle to Mary and Edith,” Gareth Neame, managing director of Carnival Films, told The Huffington Post in a statement. “We can’t wait to see him work alongside Shirley MacLaine, who are both sure to upset the Grantham’s apple cart in this year’s finale.”

Giamatti is no stranger to period pieces. In 2008, he played the lead role in the HBO miniseries “John Adams,” which earned him a Primetime Emmy, Golden Globe and Screen Actors Guild award.

In addition to Giamatti, many new characters will be introduced in the upcoming season of “Downton Abbey” set to premiere January 5. These will include Lord Gillingham, a love interest for Mary and a family friend of the Crawleys played by Tom Cullen; Lady Shackleton, an old friend of Violet Crawley; Charles Blake, an aristocrat played by Julian Ovenden; Green, a valet played by Nigel Harman; and the Duchess of Yeovil played by Joanna David.

The show will also welcome its first black character, a jazz singer named Jack Ross, which will be portrayed by Gary Carr.

“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 Abbey in Season 4,” Gareth Neame, executive producer, said in a statement, according to People magazine.

One character that fans will notice is missing when the series returns is Lady Grantham’s maid Sarah O’Brien, which has been played by actress Siobhan Finneran since its first episode in 2010. In March, Finneran revealed in an interview with the Daily Mail that she quit the show because she was tired of the role.