Mark Gatiss is an English actor, comedian, screenwriter, director, producer, and novelist. He was born on 17 October 1966.

Gatiss is renowned for his acting work on stage and screen, and for co-creating television shows with Steven Moffat. His contributions have earned him several prestigious awards, including two Laurence Olivier Awards, a BAFTA TV Award, a Primetime Emmy Award, and a Peabody Award.

One of his major works is the co-creation, co-writing, and acting in the BBC comedy series The League of Gentlemen (1999–2002). He also co-created and portrayed Mycroft Holmes in the BBC series Sherlock (2010–2017) and Frank Renfield in the BBC/Netflix miniseries Dracula (2020). Gatiss penned several episodes of Doctor Who during Steven Moffat's tenure as showrunner and two episodes during Russell T Davies's earlier tenure.

His other notable TV roles include Tycho Nestoris in Game of Thrones (2014–2017), Stephen Gardiner in Wolf Hall (2015), and Peter Mandelson in Coalition (2015).

Gatiss has expressed his talent in films like Victor Frankenstein (2015), Denial (2016), Christopher Robin (2018), The Favourite (2018), The Father (2020), Operation Mincemeat (2021), and Mission: Impossible – Dead Reckoning Part One (2023).

On stage, he portrayed Menenius in the revival of William Shakespeare's Coriolanus (2013), earning a Laurence Olivier Award nomination for Best Actor in a Supporting Role. He also played King George III in the Alan Bennett play The Madness of George III (2018) and Sir John Gielgud in the Jack Thorne play The Motive and the Cue (2023), for which he won the Laurence Olivier Award for Best Actor. His other theatre roles include performances in The Recruiting Officer (2012), The Vote (2015), and A Christmas Carol: A Ghost Story (2021).