Martin Freeman has thrown into question much of what we thought we knew about where Sherlock will go next.
Co-creators Mark Gatiss and Steven Moffat told us earlier this year that they had already produced outlines for series four and five of the BBC detective drama – which ended in January with the apparent return of Moriarty – and the assumption has been that questions about the arch-villain will be answered at the beginning of the fourth season.
But Freeman now says that the next viewers see of himself and co-star Benedict Cumberbatch in the roles of John Watson and Sherlock Holmes could be a one-off episode.
"Mark Gatiss may beat me up," Freeman told Alan Carr at the recording of this Friday's Chatty Man for Channel 4, "but there is an idea for this one-off special that’s such a good idea, and as I was listening to it I thought 'we’ve just got to do this'. And I don’t know when we are going to be able to do it, unfortunately.
"It’s a fantastic, really mouth-watering idea. But I really don’t know when we are going to get to do it."
Freeman's repeated claims that the next instalment of Sherlock could be a long way off will not surprise fans – there have traditionally been two years between series and he and Cumberbatch's diaries become busier and busier as both their stars continue to rise.
What is new is the idea of a one-off special that could perhaps clear up the enigmatic final scenes of series three, in which Andrew Scott's supposedly dead villain Moriarty appeared in an animation on TV sets and electronic billboards around London, before the man himself was glimpsed in the last moment of the episode.
Another possibility is that Gatiss and Moffat are lining up a much-talked-about Sherlock Christmas special, with Gatiss having made no secret of the fact that Yuletide episode The Blue Carbuncle – a well-loved mystery involving a Christmas goose and a valuable stolen gem stone – is among his favourite of the original Sherlock Holmes adventures.