Catrin Stewart is a Welsh actress, known for playing Jenny Flint in the BBC science fiction series Doctor Who (2011–2014), Emma Morris in the Sky One comedy drama Stella (2012–2017) and PC Gina Jenkins in the S4C crime drama Bang (2017–2020). She also portrayed Lily in Misfits (2010–2011).

"The Crimson Horror" is the eleventh episode of the seventh series of the British science-fiction drama Doctor Who. It was written by Mark Gatiss and directed by Saul Metzstein, and was first broadcast on BBC One on 4 May 2013. It marks the 100th episode, including specials, since the return of Doctor Who on 26 March 2005.