VIDEO: Teaser - DOWNTON ABBEY's Season 4 Christmas Special

SPOILER ALERT! "Downton Abbey" has just released the new teaser for its upcoming season 4 Christmas special, which will air for two hours on ITV on December 25th. But if you live in the US and haven't seen season 4, you might want to steer clear of the teaser for now to avoid spoilers. The Christmas special will air here as the final episode of season 4's run on PBS' Masterpiece. Season 4 begins January 5, 2014. Click below to watch the teaser!

On the season 4 of the historical drama, Emmy, Golden Globe and SAG award-winner Paul Giamatti (John Adams, Sideways, Barney's Version, Cinderella Man) will join the cast portraying Cora's maverick, playboy brother Harold, starring alongside the iconic Shirley MacLaine and the regular cast members.

Downton Abbey is a Carnival/Masterpiece Co-production. It is written and created by Julian Fellowes. Gareth Neame and Julian Fellowes are Executive Producers.