While the three-episode Season/Series 4 of Sherlock is still a long way off, fans can look forward to the show's upcoming "through the looking glass"-style special set back in the original Sherlock Holmes time period. We're still not sure when it will air (executive producer Mark "Mycroft' Gatiss once stated it was to be a Christmas special), though creator Steven Moffat did have a few tidbits to share about it during a recent Q&A session at the summer TCA Press Tour.

"It's probably Christmas-ish," Moffat told the ballroom full of TV critics. "We don’t actually know. We’re not making this up.”

So what was the inspiration for setting this particular Sherlock tale in Victorian times? "Just because we can, really," Moffat explained. "Mark [Gatiss] and I were having a fun day on set because he was doing some second unit shooting with some evil monks. It was the prequel, and because I think we found an old prop that was on the original Titus, so we were having a geek day. Gosh, what a surprise. And then we just thought 'could we ever just do maybe one scene or some dream sequel or something?' And then we just thought, you know, 'why don't we just do it? Why don't we just do a Victorian one?'"

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Martin Freeman and Benedict Cumberbatch as Victorian Watson and Holmes.

So aside from the different era and look, will Sherlock and Watson be behaving differently? Will their dynamic alter in any way? Moffat explained: "[Sherlock] the manners of the Victorian gentleman, which he doesn't have in the modern version. So he is a lot less brattish when he's back then. And Dr. Watson is a bit more upright. They're the same people, seen through the prism of a different time and fitting in to a different society. I would say this Sherlock is a little more polished, and he operates like a Victorian gentleman instead of a posh, rude man, which he does in the modern too."

Will there be any explanation for the period setting? "We never bothered to explain what we were doing in modern day London," Moffat said. "So why do we have to bother explaining what they're doing in Victorian London, when that's where they're supposed to be? So can we can we increase our normal massive run of three episodes to a record‑breaking four, and do the special, which is separate from the rest of the series, and done in the correct period?"

"Really, this is a one‑off," he added. "Unless we go mad and decide on setting it in the 1940s and have them fight Hitler. Nothing is inconceivable if you have no taste. But, no, we go back to doing the show normally next year, unless I'm lying or we change our minds."