Sherlock series three: new details revealed The third series of the BBC's hit drama Sherlock will begin with an episode based on Arthur Conan Doyle's book The Adventure of the Empty House, the series' co-creator Mark Gatiss has revealed. The new series, in which Benedict Cumberbatch and Martin Freeman will reprise their roles as Sherlock Holmes and Dr Watson, is due to begin filming in early 2013. "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. Season two of the BBC series ended earlier this year with an episode titled The Reichenbach Fall based on the Conan Doyle 1893 book The Final Solution. In that book Conan Doyle killed off his most famous creation after a confrontation with his nemesis Moriarty in the Swiss Alps. The corresponding BBC episode saw the famous sleuth apparently falling to his death from the roof of St Bart's Hospital in London, before re-emerging alive at the end of the episode. But ten years after the publication of The Final Solution Conan Doyle bowed to public pressure and brought Holmes back to life in the 1903 story The Adventure of the Empty House. Gatiss also added that Watson's reaction to the return of his friend Holmes in season three would differ from that in the original book. "I always found it a little unlikely that Dr Watson's only reaction was to faint for instance - as supposed to possibly a stream of terrible swear words," he said. Click here to follow Telegraph TV on Twitter