->''"Some facts in life are immutable. One is, trust no-one who uses the word 'trope'."''
-->--'''[[https://twitter.com/Markgatiss/status/511831745344573440 Mark Gatiss]]'''

British writer and actor born on October 7, 1966, Mark Gatiss is a [[OopNorth Darlington]] man best known for three things:
* ''Series/TheLeagueOfGentlemen''
* ''Series/DoctorWho''
* ''Series/{{Sherlock}}''

Gatiss is a long-time big ''Doctor Who'' fan, to put it mildly; he has written for eight of the Doctors, wrote and acted in three official approved spoofs and contributed to seven ''AudioPlay/BigFinishDoctorWho'' audios. Topping all of that though are his writing credits for the television show proper; [[Recap/DoctorWhoS27E3TheUnquietDead "The Unquiet Dead"]] for Nine, [[Recap/DoctorWhoS28E7TheIdiotsLantern "The Idiot's Lantern"]] for Ten, [[Recap/DoctorWhoS31E3VictoryOfTheDaleks "Victory of the Daleks"]], [[Recap/DoctorWhoS32E9NightTerrors "Night Terrors"]]", [[Recap/DoctorWhoS33E8ColdWar "Cold War"]] and [[Recap/DoctorWhoS33E11TheCrimsonHorror "The Crimson Horror"]] for Eleven [[Recap/DoctorWhoS34E3RobotOfSherwood "Robot of Sherwood"]], [[Recap/DoctorWhoS35E9SleepNoMore "Sleep No More"]], and [[Recap/DoctorWhoS36E9EmpressOfMars ''Empress of Mars'']] for Twelve.

He provided an uncredited voice for a space spitfire pilot in "Victory of the Daleks" and [[Recap/DoctorWhoS32E7AGoodManGoesToWar "A Good Man Goes to War"]], as well as other roles in [[Recap/DoctorWhoS29E6TheLazarusExperiment "The Lazarus Experiment"]] and [[Recap/DoctorWhoS32E13TheWeddingOfRiverSong "The Wedding of River Song"]] (the latter under a pseudonym and heavy prosthetics). His largest ''Doctor Who'' role to date was as The Captain in Twelve's regeneration story [[Recap/DoctorWho2017CSTwiceUponATime Twice Upon A Time]]. That makes him the ''only'' person to write ''and'' appear in the ''Doctor Who'' TV series no less than five times.

And as if that wasn't enough, he's also the first person to play ''both'' the Doctor (in "The Web of Caves", a comedy spoof) and the Master (in [[Recap/BigFinishDoctorWhoUnboundE2SympathyForTheDevil "Sympathy for the Devil"]], a Creator/BigFinish WhatIf audio). Also of note in this department, is the fact he can do a pretty much dead-on Anthony Ainley impression.

He appeared in a [[LiveEpisode live version]] of ''Series/TheQuatermassExperiment'' in 2005 with Creator/DavidTennant. During a break in rehearsals, Tennant whispered to him that he was the new Doctor that Gatiss would write "The Idiot's Lantern" for.

Also appears in the fourth and fifth series of ''Series/HorribleHistories'', along with fellow ''League of Gentlemen'' stars Reece Shearsmith and Steve Pemberton.

He is also one of the two creators of ''Series/{{Sherlock}}'', and plays the character of Mycroft Holmes.

He has a minor role in ''Series/GameOfThrones'', playing Braavosi banker Tycho Nestoris.

Aside from fiction, he also wrote and presented the BBC documentary ''[[http://en.wikipedia.org/wiki/A_History_of_Horror A History of Horror]]'' detailing the genesis and evolution of horror films over the last century.

Outside of television, he's the author of a series of TwoFistedTales-style detective novels, starring LoveableRogue spy Lucifer Box. It's been described as "''SherlockHolmes'' [[JustForFun/XMeetsY meets]] ''{{Literature/Flashman}}'' in [[Film/IndianaJonesAndTheTempleOfDoom the Temple of Doom]]".

His partner is actor Ian Hallard, who (of course) has appeared in ''Doctor Who'' and also in the ''AudioPlay/{{Gallifrey}}'' audio series.

!!This actor's work provides examples of:
* AwesomeDearBoy: He said that his role on ''Series/{{Being Human|UK}}'' was his favorite. He said that since he grew up a huge fan of Creator/ChristopherLee and Film/HammerHorror films, getting to play the ''Being Human''-verse equivalent of Dracula was a dream come true.
* DyeingForYourArt: Dyed his hair darker for the part of Mycroft Holmes in ''Series/{{Sherlock}}''.
* OldShame: His and Creator/DavidWalliams' 1999 ''Series/DoctorWho'' sketch "The Pitch of Doom" had a line in which Walliams' character seemingly dismisses the post-Creator/TomBaker Doctors as talentless nobodies. He regretted the line as soon as the sketch was broadcast, and ensured that it was removed for all subsequent airings.
* PromotedFanboy: He was a BigNameFan of ''Series/DoctorWho'' well before he started writing for first the spin-offs and then the TV revival, and was also a big fan of ''Literature/SherlockHolmes'' before writing ''Series/{{Sherlock}}''
* TrollingCreator: Has been taking lessons in the art from Creator/StevenMoffat. And acing them. Damn him.
* WrittenByCastMember: Co-wrote ''Series/TheLeagueOfGentlemen'', ''Series/DoctorWho'' and ''Series/{{Sherlock}}''.