Born: 17th October 1966
Episodes Broadcast: 2005-2007, 2010-2015, 2017

Mark Gatiss was born in Sedgefield, County Durham and became a Doctor Who fan after watching Spearhead From Space, Jon Pertwee's 1970 debut as the Third Doctor, at the age of three. He took to the stage while still in primary school, ultimately completing an honours degree in theatre arts at Bretton Hall College. Gatiss made his television debut with a 1993 episode of Harry. After appearing in The Dwelling Place, however, he struggled to find work. Instead, Gatiss co-founded a comedy troupe called the League of Gentlemen with several of his college classmates. Initially a stage act, their award-winning performance at the Edinburgh Festival Fringe in 1997 led to a radio series.

In addition to acting, Gatiss was an avid writer from a young age. He wrote four original Doctor Who novels for Virgin Publishing and BBC Books, the first of which was 1992's Nightshade, a Seventh Doctor adventure for the Doctor Who: The New Adventures range. Gatiss both wrote and acted in several direct-to-video and audio dramas from BBV, appearing alongside a number of Doctor Who alumni. The first of these was The Zero Imperative in 1994. His involvement with BBV led Gatiss to accompany Sylvester McCoy to Vancouver, where he filmed his final scenes as the Seventh Doctor for the Doctor Who (1996) telefilm. Gatiss' chronicle of the trip took the form of the 1996 documentary Bidding Adieu. In 1999, Gatiss wrote one of the first Doctor Who audio plays for Big Finish Productions, a Fifth Doctor story called Phantasmagoria. The same year, The League Of Gentlemen transferred to television on BBC2. As such, when the channel was assembling a Doctor Who night that November, Gatiss was a natural choice to participate in a series of comedy sketches, one of which saw him dress up as an ersatz Doctor.

In 2004, Gatiss published the first book in a trilogy of novels about secret agent Lucifer Box

Gatiss' acting career was also finding new life away from the League of Gentlemen. He could be seen in Lenny Goes To Town and In The Red during the late Nineties, while his credits soon after the turn of the century included Spaced, Dr Terrible's House Of Horrible, Agatha Christie's Marple and Nighty Night. He both wrote for and acted in the revival of Randall & Hopkirk (Deceased), and script edited the first season of Little Britain. Gatiss' movie debut came in 2001's Birthday Girl with Nicole Kidman; his other films during the decade included Bright Young Things, Match Point and Starter For 10, plus The League Of Gentlemen's Apocalypse. In 2004, he published The Vesuvius Club, the first book in a trilogy of novels about secret agent Lucifer Box.

Early in the new century, Gatiss and fellow fans-turned-professionals Gareth Roberts and Clayton Hickman collaborated on a proposal to bring Doctor Who back to television. Although it was unsuccessful, in 2003 Gatiss was nonetheless recruited for the new season of Doctor Who being overseen by executive producer Russell T Davies. Drawing upon his love of Victoriana, Gatiss wrote the eerie The Unquiet Dead, a 2005 adventure for Christopher Eccleston as the Ninth Doctor. The following year, he contributed The Idiot's Lantern for David Tennant's Tenth Doctor; he and Tennant had recently co-starred in a remake of The Quatermass Experiment. In 2007, Gatiss became only the second person to have both writing and acting credits on Doctor Who, when he played the eponymous villain of Stephen Greenhorn's The Lazarus Experiment. He also developed a third Doctor Who script, entitled “The Suicide Exhibition”, only to see it replaced by James Moran's The Fires Of Pompeii. More happily, Gatiss married actor Ian Hallard in 2008; he would later appear in the Gatiss-scripted An Adventure In Space And Time and Robot Of Sherwood.

In the latter part of the decade, Gatiss both wrote for and acted in the horror anthology Crooked House -- with which he added producer to his resume -- and Poirot. He could also be seen in Sense & Sensibility, Clone, Psychoville and Jekyll. The latter was made by frequent Doctor Who contributor Steven Moffat, and he and Gatiss began developing Sherlock, a modern-day spin on Arthur Conan Doyle's iconic detective. Gatiss would write eight episodes, and appear as Sherlock's supercilious elder brother, Mycroft. At the same time, Moffat replaced Davies as Doctor Who's showrunner, and he invited Gatiss back to the programme. Four adventures for Matt Smith's Eleventh Doctor resulted, with 2013 alone boasting both Cold War, in which the Ice Warriors returned after a forty-year absence, and The Crimson Horror, which Gatiss later novelised for BBC Books. The same year, Gatiss was the writer and executive producer of his passion project: An Adventure In Space And Time. A docu-drama chronicling the early years of Doctor Who, it was broadcast as part of the programme's fiftieth-anniversary celebrations. In front of the cameras, Gatiss could also be seen -- barely -- when he made a cameo appearance beneath prosthetics as the ill-fated Gantok in 2011's The Wedding Of River Song; his presence was further masked by the use of the alias “Rondo Haxton”.

Gatiss made a valedictory appearance as Captain Archibald Lethbridge-Stewart in Twice Upon A Time

Gatiss' association with Doctor Who continued after Peter Capaldi became the Twelfth Doctor. He wrote three more scripts for the series, and then made a valedictory appearance as Captain Archibald Lethbridge-Stewart -- forebear of the Doctor's longtime ally, Brigadier Alistair Lethbridge-Stewart -- in 2017's Twice Upon A Time, the last story for both Capaldi and Moffat. Elsewhere during the 2010s, Gatiss earned his first credit as a director on the Christmas Day ghost story The Tractate Middoth. He wrote, produced and performed in The First Men In The Moon, and was also multiply-billed on Queers, as writer, producer and director. Other television appearances included Mapp & Lucia, Wolf Hall, Taboo and Game Of Thrones. Gatiss also participated in the 2017 revival of The League Of Gentlemen. Amongst his movie roles were Victor Frankenstein, Dad's Army, Christopher Robin and the critically-lauded The Favourite. Gatiss' success extended to the stage, where he won the Laurence Olivier Award for Best Supporting Actor for Three Days In The Country.

Gatiss' career continued at speed into the Twenties, when he again collaborated with Moffat on Dracula. His services as an actor were increasingly in demand for feature films, including the Oscar-nominated The Father with Anthony Hopkins and Olivia Colman, and the action sequel Mission: Impossible 7.