Sherlock actor Andrew Scott has revealed fans quizzed him on a daily basis over a possible return as Jim Moriarty to the hit BBC drama.
Sir Arthur Conan Doyle's famous detective, played by Benedict Cumberbatch, locked horns with Moriarty for the show's first two series before the super-villain supposedly killed himself in The Reichenbach Fall.
He returned to the show in Sunday night's series four finale as part of a flashback sequence.
Speaking at a screening of the episode alongside several of the show's stars and co-creators Mark Gatiss and Steven Moffat, Scott said he had "spent the last six months under wraps".
Asked how often fans quizzed him over his mooted return to the show, the 40-year-old said: "I'd say every day."
The concluding episode saw Moriarty team up with Sherlock's secret sister Eurus, played by Sian Brooke, before he died.
The pair enticed the detective, Martin Freeman's Dr John Watson and Mycroft Holmes (Gatiss) into a series of games.
A final twist was also revealed as Sherlock's long-referenced dog, Redbeard, was discovered to be a fourth Holmes sibling who had been killed by Eurus.
Gatiss said the plot twist had originally been a joke that had turned into a "monstrous" storyline.
"I remember being in Beryl's (executive producer Beryl Vertue) flat talking about something else and I said 'what if Redbeard is not a dog'.
"Redbeard began as a joke, it was a little reference to the fact that Sherlock thought his pet dog had gone to live on a farm.
"Sometimes you plant the seed and it grows into a monstrous thing," he added.
The future of the show is in doubt following the episode, with Moffat saying "we're not planning it to be (the final), but it might be".
He added: "We could end it there. We couldn't have ended it on any of the previous series because they always ended in walloping great cliffhangers, usually by Andrew."
Meanwhile Gatiss added that the show had deliberately been left open to any follow-ups.
He said: "I think what's actually happened is we have now done the story of how Sherlock Holmes and Doctor Watson that we have always known became those men.
"The reason we leave it at Rathbone Place is that actually if we do come back, and we would love to come back, we could absolutely very easily start it off with a knock on the door and Sherlock saying to John 'do you want to come out to play'."