DOWNTON ABBEY Season 4 News, Paul Giamatti Joins Cast (SPOILERS): 'John Adams' Star Will Debut in 2014 Finale Opposite Shirley MacLaine

Emmy Award-winning actor Paul Giamatti might be in the headlines for suiting up in The Amazing Spider-Man 2 as the villainous "Rhino," but news of him being cast in a more down-to-earth role has just broke. The 46-year-old actor will be appearing in the season 4 finale of PBS's "Downton Abbey." Giamatti, who usually portrays curmudgeon-type characters, will be playing against-type as series regular Cora's (played by Elizabeth McGovern) "a maverick, playboy brother Harold."

"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," said Gareth Neame, managing director of Carnival Films (a co-producer of the "Downton Abbey").

Neame also gave fans a little hint as to how Giamatti's character would cause some trouble for the main characters.

"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," he teased.

Giamatti has some other projects coming out and in the works, too. He is set to portray  Friar Laurence in the upcoming adaptation of Romeo and Juliet and he will also appear as part of the star-studded cast of the film Saving Mr. Banks.

Besides Giamatti joining the PBS hit, next season will introduce a slew of new cast members including Dame Kiri Te Kanawa, Tom Cullen, Julian Ovenden, Nigel Harman, Joanna David and Gary Carr.

This group of newcomers will be joining returning cast members Shirley MacLaine, Michelle Dockery, Elizabeth McGovern, and Hugh Bonneville (to name a few).

Season four of "Downton Abbey" will kick-off on January 5, 2014 (in the United State).