So we're all well aware of how amazing Andrew Scott is as supervillain Moriarty in Sherlock - but did you know that he was so incredible, an episode was rewritten just to showcase his talents?
Apparently, Andrew knocked the socks off series creators Mark Gatiss and Steven Moffat at his audition, earning himself a much bigger part than he was ever supposed to have.
Steven was speaking at a Bafta event promoting the fourth season of Sherlock when, according to the Radio Times, he revealed how the now famous episode The Great Game came to feature Moriarty telling Benedict Cumberbatch's super sleuth in menacing tones: "I will burn you. I will burn the heart out of you."
He said: "We didn't really have a scene for Moriarty in the original version of The Great Game. It was going to be a big reveal that that young fella you'd met earlier, that camp young fella, turns out to be Moriarty, but you don't see him in his own form."
Producer Sue Vertue added: "He was just going take his sunglasses off [as an indication]."
Steven went on: "So we concocted a ludicrous scene where Moriarty's being bonkers, and saying things, you know 'I will burn the heart out of you', on the basis that this is going to be the kind of nonsense that he's going to have to say in the future.
"And a bunch of actors came in, did fine. Presumably stared at the script and said 'Dear God.' But Andrew absolutely went for it. And we thought, not only are we going to cast him, but by some means we're going to include that scene in the episode.
"And we rewrote the end of the episode so that Moriarty... for no particular reason, turns up in the swimming pool, is going to kill them, changes his mind and goes away again."
And such was our introduction to the maniacal nature of Sherlock's nemesis.
Sherlock returns on New Year's Day at 8.30pm on BBC One.