SPOILERS! DO NOT READ IF YOU HAVEN'T WATCHED SHERLOCK SEASON FOUR EPISODE TWO
Sian Brooke, the actress who tricked us all by appearing as three separate characters on Sherlock with some clever costume changes, wigs and contact lenses, has opened up about being cast as Sherlock's secret sister Eurus.
As fans of the show will know, we unknowingly first saw Eurus as she caught John Watson's attention on the bus, leading him to text her behind his wife Mary's back. She also played villain Culverton Smith's daughter Faith, who goes to Sherlock for help with her father, as well as John's therapist. Most viewers had no idea that the three characters were actually being played by the same actress, who was revealed to be Eurus - the sister of Sherlock and Mycroft - in the last shocking moments of Sunday's episode. However, Sian herself has revealed that she had no idea she was auditioning for just the one role, but was under the impression that the girl on the bus, the therapist and Faith were all separate parts.
Sherlock's secret sister was revealed at the second of last week's episode
"It was amazing," she said. "I kept coming in for these meetings, these secret meetings, and thinking, 'Why am I [being asked to audition for all these parts]? Oh, there's just a couple of parts and a big part', that's what I thought. I thought, 'Well, it's a part in Sherlock, lovely.' And then when they actually revealed what it was I was like, 'What? What?! What?!'" The show's co-creator Mark Gatiss confirmed that they kept the secret under wraps by not telling anyone who was auditioning about the role. He said: "We got Sian, and a lot of other people to audition… as if there were several parts, like Faith and the girl on the bus. And then it was only at the eleventh hour that we said 'Actually they’re all the same person.'" Sian continued: "When I found out I’d got the part I felt exceptionally lucky to be part of something, to join something that I'd loved for such a long time. And then when I discovered exactly what it was I couldn't quite believe it. I didn't find out until I got the part that I was going to be his sister. It was a revelation!"