Andrew Scott has revealed he gets "lovely" fan mail from Sherlock fans - despite being such a villain.
The Irish actor stars opposite Benedict Cumberbatch as the detective's nemesis Moriarty, but is still a big hit with viewers.
Andrew revealed: "Most of the letters I get are really lovely. People are very passionate about it. I've been very touched by what people are saying.
"People can get very creative and create an online community. Everybody gets passionate about something. I think it's cool for young people to have something that connects them one to another if they're really passionate about it."
Andrew voices the role of a senior MI5 agent in new 10-part audio political thriller 6 Degrees Of Assassination.
He revealed: "Alex is a senior counter terrorism officer of MI5 and he carries with him a certain amount of guilt and shame about 7/7 and his involvement in that.
"I think he's a very talented guy; he's a family man but, as with a lot of these guys, he goes through a lot of difficulty with his personal life because the job takes over so much. It is a very addictive and a very exciting life."
:: 6 Degrees Of Assassination also stars the voices of Doctor Who's Freema Agyeman and Spooks' Hermione Norris and is available for free at www.audible.co.uk/assassination from Monday November 24.