Dec. 9, 2013 at 9:37 AM ET
It's not going to be all tea and crumpets when "Downton Abbey" returns for season four, actor Brendan Coyle, who plays beloved valet Bates, revealed to TODAY in an exclusive preview from the UK set.
"We can't give anything away, but there's a very dark and very serious dramatic twist," Coyle told TODAY's Andrea Canning.
There are rumors aplenty, including rape and murder ... and that Bates may go bad. (Well, he does have a murky past and a prison record.) And it wouldn't be "Downton" if there wasn't some legal red tape making everyone's life difficult.
"Matthew, we believe, died without a will," said Hugh Bonneville (Lord Grantham), "and that's a major problem."
Matthew Crawley, as fans will remember, was the catalyst for conflict from the first season, when Downton was seemingly left without a male heir to the title. Digging into the family tree uncovered the unassuming lawyer, who slowly grew to like the idea of becoming a lord. Alas, following his marriage to Mary (and the birth of their son), he was killed at the end of last season in a car accident after actor Dan Stevens decided to leave the show.
"His departure gave us something very interesting for Mary to do," said show co-creator Julian Fellowes. "We are allowed to accompany her on her road out of the trauma and out of the grief."
Meanwhile, American celebrities are making their presence felt on the show. Shirley MacLaine first showed up last season, and next year will feature Paul Giamatti as Lady Cora's brother. So who else would the cast like to see guest star?
"I would start with P. Diddy," said Coyle.
"George Clooney, Matt Damon, Bill Murray," Bonneville added.
And what about Matt Lauer or Al Roker? "I'd like to think they would be very high up in the servant hierarchy," laughed Elizabeth McGovern, who plays Cora.
"Downton Abbey" returns on Jan. 5 on PBS.