It looks like the new series of 'Sherlock' may have started filming.
Co-creator Mark Gatiss tweeted a picture of a skull wearing an old-fashioned optician's lens frame, with the caption "I spy Series Four... #Sherlock"
However, one wag was quick to point out the long times fans have to wait for new series of the show to start. They quipped that the skull was actually "A Sherlock fan waiting for series four".
The series does take its time coming to air. Fans will surely be glad that filming is finally under way, even if there are still months to wait before they can see it.
The most recent episode was the special that aired over Christmas. Titled 'The Abominable Bride', it was set in Victorian London, though it flitted between then, the modern day and strange sequences that seemed to take place inside Sherlock Holmes' head.
It had a mixed reception, so fans will undoubtedly be looking forward to getting back to business as usual. Let's hope we don't have too long to wait...