Ellison is perhaps best known for playing Emily Shadwick in the television soap opera Brookside until 2003, and as Meg Giry in the 2004 film adaptation of The Phantom of the Opera. She has achieved examination passes with the Royal Academy of Dance and appeared on instructional videos for the academy. Ellison had a run in the London West End theatre version of the musical Chicago in 2004 at the Adelphi Theatre, and returned from 10 July to 9 August 2006 again playing the leading role of “Roxie Hart”, this time at the Cambridge Theatre. Ellison subsequently toured England in Chicago from 25 September 2006 until 5 May 2007. On 1 October 2007, Ellison joined the cast of a revival of Boeing Boeing at the Comedy Theatre, London, playing the part of Gloria, an American TWA air stewardess. Ellison featured in the Liverpool Empire Theatre’s Pantomime Cinderella for 2008, opposite Cilla Black and Les Dennis.