One of the things that got "Sherlock" star Benedict Cumberbatch excited about doing the Christmas special this year was the fact that he can change his hairstyle. Given that the show's producers planned to take the series back to its original setting as opposed to having it set during modern times, everything had to imbibe the Victorian setting - including the stars' hairstyles.

Of course, as excited as he was to get a new hairdo, Cumberbatch also thought that show creators Steven Moffat and Mark Gatiss were crazy for shifting the setting.

"I was really excited about getting to change my hair," he smilingly told Express UK. "I said, 'Oh good, so I can have a haircut and push it back off my face?' And they went, 'Maybe.' But beyond that I thought they were mad. I thought they were truly crazy."

The Christmas special called "The Abominable Bride" is set in 1895 and the story will focus on a man named Thomas Ricoletti. Ricoletti's wife recently committed suicide, but for some strange reason, she appears to have returned and her "ghost" is keen on getting revenge.

With just a few more days to wait before the episode airs, Cumberbatch refuses to spoil any surprise and encouraged fans to just wait and see what will happen.

"The minute I read it, it was clear what they were trying to do and I thought it was fantastic," he said. "In fact it's thrilling, because a lot of the heavy lifting is done for you. It's Holmes in his natural time and era. I don't feel like I'm trying to carry the thing that the modern version does, where he's a Victorian man in a modern era.

Cumberbatch added, "It's very nice to have the language and the kit and the environs of where he really belongs."

Gatiss revealed that Cumberbatch was not the only one who had reservations with the Christmas special when the idea was first pitched. "There was a little bit of resistance from the BBC, (thinking) 'are we just going mad here?' But the key is it's absolutely the same show - same sensibility, same humour, same people," he said.

Moffat confirms that "The Abominable Bride" still has all the ingredients that "Sherlock" fans had come to grow and love. "It really doesn't change the show. Within a few minutes it's just Sherlock Holmes," he assured.

"The Abominable Bride" will air on BBC on January 1, 9 p.m.