Last Thursday (12 January) Steven Moffat and Mark Gatiss attended the BFI's special preview of the episode - titled 'The Final Problem' - ahead of its showing on BBC One last night where they broke down all of the revelations as well as teasing the likelihood of an unconfirmed fifth season.
Most of the assembled crowd wanted to know about Eurus (Sian Brooke), the character revealed to be Sherlock and Mycroft's sister in episode two.
He continued: "He isn’t as smart as Eurus or Mycroft, he’s just always going to win against them because he is better and stronger and that is him becoming the Sherlock Holmes of Basil Rathbone and Jeremy Brett… The wise old man of Baker Street we’re used to who’s still terrifying and cold but has a heart that we never doubt.”
Discussing the scene in which Sherlock (Benedict Cumberbatch) utters the words "I love you" to pathologist Molly Hooper (Louise Brealey), Moffat revealed how, originally, there was "a completely different scene there, and two people liked it. That was me and Mark. Everyone else hated it.
"On the very last day we spent writing this episode, we started looking at it and said, ‘You know what? Everybody thinks this is shit. Let’s just go to our office and think of something else.’ So we did and it became ‘That’s the best scene in the episode.’ That’s the value of getting really negative feedback.”
Gatiss expressed his view on this moment nicely, saying: “...evil met evil across a glass divide and morphed into one another.”
“It was actually very good that we don’t see the conversation. The idea of just seeing them physically size each other up is a little more interesting.”
Of course, with season four now complete, fans are sitting tight for news on a fifth. Could 'The Final Problem' be Sherlock and Watson's final outing?
Moffat thinks that's a possibility: “If this is the last time - and I’m not planning on it to be, but it might be - it is possible that we could end it."
“We couldn’t have ended it on any of the previous series because there was what have been great cliffhangers.”
If you're feeling empty now Sherlock's ended, take a look at our guide to all the TV shows you should be watching in 2017.
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