When "Sherlock" returns to the air in December for its special Christmas episode, so too will Martin Freeman's mustache.

Well, not exactly; the special, which takes place in Victorian era London, will feature both Benedict Cumberbatch's titular Sherlock and his right hand man John Watson in full on period piece garb. And for the latter, that means facial hair suitable for the time period, as seen in a new photo for the BBC One drama, debuting via Metro.

A previous photo from the set of the special featured Cumberbatch dressed like his character's 19th Century incarnation, deerstalker cap and all. The episode will be followed by a new, three-episode series.