Fans of Downton Abbey can expect the series to take a dark turn, thanks to a "harrowing" new storyline centred around Thomas Barrow.
Rob James-Collier, who plays the sometimes sinister under-butler, admitted that he has been suffering sleepless nights over the script, which sees his character question - and try desperately to change - his sexuality.
"There are mornings of those scenes when you haven't been able to sleep at night because you are so worried about how it will go," James-Collier told the Daily Mail.
"Thomas comes right up to the abyss."
"It's quite a harrowing storyline and I hope it is. Because if it isn't, I haven't done it justice."
His quotes come just days after Hugh Bonoville - who plays Robert, Earl of Grantham in the show - said he believed the show could have another five years left to run.
"This is all written by one person and there's only so much one person can do," he said.
"There will be an end. (Executive producer) Gareth Neame has said he reckons it will run between five and ten years, so we've made it to halfway.
"I think there will be natural end and I'm sure Julian will want to quit while he's ahead."
Fellowes himself has said that "the most important thing is to make sure Downton is well-formed, comes to an end at the right time, and is not lured into the usual thing of trying to keep something going past its time".
- Independent