 The eldest of his siblings (his younger brother Richard is also an actor), he grew up in West Wickham, Kent.At school, Dillane began performing in end-of-term plays and had "a certain facility" for funny accents.He often found himself in women's roles, which he says "wasn’t good for my confused adolescent psyche", but also recalls a part in "Rosencrantz and Guildenstern Are Dead" as being particularly memorable, noting that shouting "Fire!"