Here's The Creators Of "Sherlock" On What The Fuck Just Happened

FULL of spoilers. Do not read until you have finished with "The Lying Detective".

Seriously. Do not scroll down until you have watched the end of the Sherlock episode "The Lying Detective".

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NO SERIOUSLY.

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At the end of the episode, we found out that the woman who Watson (Martin Freeman) was sending flirty texts to...

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...had been wearing a disguise and pretending to be Watson's therapist...

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...AND pretended to be Culverton Smith’s (Toby Jones) daughter, who Sherlock thought was a drug-fuelled hallucination.

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So all the women were one person and that person happens to be...Sherlock's sister!

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Her name is Eurus.

At a Q&A following a screening at BAFTA Cymru in Cardiff, Sherlock co-creator Steven Moffat talked about Watson's fling in the first episode: "With mystical inevitability it was Sherlock's sister!"

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Sherlock's sister is played by actress Siân Brooke! The show's co-creator Mark Gatiss also explained in the Q&A that Sherlock having a sister was an idea both he and Moffat had right from the first series.

"It started as a joke years, years ago," explained Gatiss. "Right from the beginning of the first season, there was a line in 'The Great Game' when we were sort of sketching in the idea of the Holmes family and there was going to be a line about Mycroft being a member, Sherlock admitting that he was cleverer than him and then him kindly saying, mind you...my sister...

"It was absolutely cut off, and that's really where it all began.

"[At the time] we thought, we won't do too much. And thank god we didn't, as it gives us this place to go."

The shock twist scene, when her true identity was unveiled, has been an idea ever since Moffat and Gatiss were making “His Last Vow”. That's the episode where Charles Magnussen is shot by Sherlock.

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Moffat tips Brooke to become a huge star following her role in the next episode, "The Final Problem".

He also said that following the episode she is now allowed to tell others that she is in the show's cast: "She's even lied to her friends."

The biggest shock in last week's episode, "The Six Thatchers", was not just Mary's (Amanda Abbington) death, but also Watson being a bit of a dick by having an affair AND blaming Mary's death on Sherlock.

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Moffat defended this. He said: "He's a fully rounded character. He's a fully rounded human being with all the normal flaws that people have", adding that Watson in the original books by Arthur Conan Doyle could be a bit of a womaniser.

Asked by BuzzFeed whether Watson is back to his usual self in the next episode, Moffat said: "We're not going to say now that he's cosy and lovely, you don't get Martin Freeman to play that."

Gatiss added that Watson has not yet overcome the devastating circumstances surrounding Mary's death.

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"It's not the end of the process. The repercussions from Mary's death keep going."

And then there's the staggering twist that Mrs Hudson (Una Stubbs) was the one driving the car at the start of the episode, which had Sherlock in the boot.

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"I loved it. Did you like my driving?" said Stubbs at the Q&A. "When they told me that there was this car sequence, I hoped and I hoped that I was actually driving because I loved it. I haven't driven for a long time now."

Turning to Gatiss, who also plays Mycroft, she repeated the line she uttered to him in the episode: "Get out of my house. You reptile."

It was revealed that Stubbs did not drive the car; a James Bond stuntman did.

Moffat also talked about Gatiss writing a poem to The Guardian in response to a column in the paper about the show turning into something too much like the Bond films.

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"You know that utter rotten article that Mark responded to in verse, 'The Six Thatchers' being like a Bond movie and it had a three-minute punch-up.

"Which Bond movie has got a three-minute punch-up in it?"