Sherlock creator Steven Moffat revealed the three key themes of Series Three for the hit BBC One drama last Friday in Edinburgh during a masterclass on the hit show.

This Friday, the whole hour-long session, also featuring the show's co-creator Mark Gatiss, producer Sue Vertue and actor Andrew Scott (Sherlock's Nemesis Moriarty), is available to watch online (above).

Speaking to a room of TV industry insiders and journalists at the Media Guardian Edinburgh International Television Festival, Moffat spoke about how the show, starring Benedict Cumberbatch as the elusive detective and Martin Freeman as Doctor Watson, became an international success story.

Moffat said: "We love Sherlock Holmes so much - this is fan fiction! We wouldn't have minded if nobody had watched it and we'd have been able to keep making it for each other."

Watch the full masterclass above.

PHOTOS: Steven Moffat has also been busy creating Doctor Who series 7...

Loading Slideshow...
  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who series 7

  • Doctor Who

  • Doctor Who series 7