Sherlock co-creator Mark Gatiss says John Watson’s reaction to his friend's return from the dead may not be entirely positive.
The detective, played by Benedict Cumberbatch, faked his own death by leaping from the roof of a hospital at the end of series two, leaving John to mourn him. He will reveal that he is still alive in the first episode of the new series, based on Sir Arthur Conan Doyle's original story The Adventure of the Empty House. But Gatiss says Martin Freeman's Watson may not be quite as understanding as his literary counterpart.
"There's certain things about The Adventure of the Empty House which feel set in stone because that's how Sherlock comes back, but at the same time we feel free to invent and to introduce new stuff to it,” said Gatiss.
"I always found it a little unlikely that Dr Watson's only reaction was to faint, for instance - as opposed to possibly a stream of terrible swear words," he told the Press Association.
Gatiss also revealed that he and Sherlock co-creator Steven Moffat take a "magpie approach" to deciding which Conan Doyle stories to adapt.
"Everybody has their favourites, Steven and I have our all-time favourites, but it's really a question of what will fit into the structure. We're sort of guided by our idea for the overall feel of the next three stories," he explained.
Series three of Sherlock is due to start filming early next year.