Jonjo O'Neill was born in Belfast, Northern Ireland in 1978. He moved to England to study at the Guildford School of acting from 1996 to 1999. He is now a well known British stage actor and is Resident Artist with the Royal Shakespeare Company, perhaps best known for his portrayals of Richard III and as Mercutio in the acclaimed Rupert Goold production of Romeo & Juliet. Onscreen he is best known for Defiance (2008), Doctor Who (2005), The Assets (2014), The Fall (2013) and Constantine (2014).