In the theatre, Ferguson has appeared as Countess Florence/Antonescu in Terence Rattigan's Man and Boy's 2004 tour and West End run, directed by Maria Aitken; as Constanza, in the London Symphonia's 2003 production of Amadeus, directed by Jonathan Best; and as Isabelle in a 2000 production of Ring Round the Moon, at the King's Head Theatre, directed by Phil Willmott.