The most famous detective in the world, Sherlock Holmes, is to get a special episode when series four begins filming next year.

The BBC has announced that shooting will start on a special in January 2015, with three more episodes to follow later in the year.

It has been known for some time that a fourth series was in the pipeline, but what with Benedict Cumberbatch being The Busiest Man in Film, as well as committed to the serious matter of playing Hamlet on stage late next summer, and Martin Freeman wowing the world in Fargo, it is no mean feat getting the A-listers together again.

The drama is from Hartswood Films, BBC Cymru Wales and Masterpiece for BBC One.

Steven Moffat, co-creator, writer and executive producer of the show, said of the extended commission: “A special, plus a new series of three episodes – it’s a record-breaking run! Of course, it’s far too early to say what’s coming, but we’re reasonably confident that the very next thing to happen to Sherlock and John, is the very last thing you’d expect…”

More news on Sherlock series 4 will follow over the coming weeks on Production Intelligence, our online database of advance and archive productions.