Putting an end to at least some of the speculation, "Sherlock" co-creator Steven Moffat has confirmed the 90-minute special is indeed set in the Victorian era.

Fans have been scratching their heads since the first promotional image was released in November, with stars Benedict Cumberbatch and Martin Freeman depicted in period clothing. Speculation about costume parties and dream sequences was reignited in January, when Cumberbatch was photographed on location wearing the famed deerstalker.

However, Moffat insists the special takes placed during the 19th century.

“The special is its own thing,” he told Entertainment Weekly today at SXSW. “We wouldn’t have done the story we’re doing, and the way we’re doing it, if we didn’t have this special. It’s not part of the run of three episodes. So we had this to do it – as we could hardly conceal – it’s Victorian. [Co-creator Mark Gatiss] and me, we wanted to do this, but it had to be a special, it had to be separate entity on its own. It’s kind of in its own little bubble.”

The special will air late this year, although no date has been announced. It will be followed next year by a three-episode fourth season.