The BBC has released this teaser image for what appears to be a Christmas special to air in 2015, preceding a regular series in 2016. There’s no additional information provided, so whether the pair are in period dress for a party or have discovered time travel remains to be seen.

This is actually the second image released. The first was extremely similar but, if you look carefully, had a couple of digital editing mistakes that prompted fans to dub it “The Case Of The Missing Shoulder”: