Stars of BBC One drama Sherlock appear to have taken a trip through time as actors Benedict Cumberbatch and Martin Freeman pose in period costume for a forthcoming one-off special.
Although the two stars are pictured next to each other, the image appears to have been assembled from two separate shots of the stars as a montage.
The image which was posted online actually has a chunk of Cumberbatch's shoulder missing.
The BBC has previously confirmed the programme will make a return with a special followed by three more films.
Show producer Sue Vertue, who is married to writer Steve Moffat, suggested that the wheels are now in motion for the consulting detective's return by tweeting an image of its stars Cumberbatch (who plays Sherlock Holmes) and Freeman (John Watson).
She accompanied the picture with a caption which read: '#221back #Sherlock #notkidding'
Vertue also posted an image of a script for the programme, written by Moffat and Mark Gatiss, and said there had been a read-through earlier in the day.
She wrote: 'This is what we've been doing today.'
No date has been given for the film to be finished but the BBC has previously said filming will begin in January.
And there is no explanation why the pair are in period costume for the programme which has updated Arthur Conan Doyle's characters to the present day.
The third series of Sherlock finished earlier this year but fans were warned they probably face a lengthy wait due to the commitments of its in-demand stars.
The series climaxed with a flood of images of villain Moriarty - played by Andrew Scott - repeating 'did you miss me?'.
Fans have been left in suspense as he was thought to have died.