1. Since then, Dillon has performed in the West End, playing the roles of Sandy in Grease at the Piccadilly Theatre, Vivienne Kensington in Legally Blonde at the Savoy Theatre, Sally Bowles in Cabaret, Molly in Ghost the Musical at the Piccadilly Theatre, Ellen in Miss Saigon, and Betty Schaefer in Sunset Boulevard with the English National Opera.
Siobhan Dillon reprised this role at the Palace Theatre in New York City.
Siobhan Dillon's mother owned her own business in advertising after being a drama teacher.
Siobhan Dillon attended The Friary School in Lichfield where she performed in shows, but as she did not think she would become a singer, she turned to the fashion world.
Siobhan Dillon was a member of Lichfield Operatic Society and in October 2001 performed the title song from the musical Whistle Down the Wind as part of the society's show, Whistle Down the West End at The Friary School Theatre in Lichfield.
Siobhan Dillon reached the final of the show and finished in third place behind Helena Blackman and winner Connie Fisher.
However, after finalist Emilie Alford dropped out of the competition, Siobhan Dillon, being the last person eliminated during the selection process returned to the show and was given the nickname, "Second Chance Maria".
Siobhan Dillon completed the course in the fastest time of under two minutes.
Siobhan Dillon successfully got through to the second live show of the evening but faced the second sing off with Aoife Mulholland.
Siobhan Dillon was eliminated during the night's first public vote, which meant she came third overall.
Siobhan Dillon made her West End theatre debut in 2007 playing Patty Simcox in the musical Grease.
Siobhan Dillon was the understudy for the characters of Sandy and Marty and played both roles several times during her run in the show.
Siobhan Dillon returned to the production on 25 January 2010 this time taking over the lead role of Sandy from Emma Stevens.
Siobhan Dillon played her final performance on 24 July 2010 and was succeeded by Over the Rainbow contestant Lauren Samuels.
From late 2009 Siobhan Dillon took over the role of Sally Bowles in the UK tour of Cabaret from former I'd Do Anything contestant Samantha Barks.
Siobhan Dillon took over the part of Vivienne Kensington from Caroline Keiff in the West End production of Legally Blonde on 25 October 2010.
Siobhan Dillon commented about her new role in a London theatre interview.
On 11 May 2015, Siobhan Dillon took over the role of Ellen in the West End revival of Miss Saigon.
Siobhan Dillon played the role of Betty Schaefer in Sunset Boulevard at the London Coliseum, which opened on 4 April 2016.
Siobhan Dillon made her Broadway debut in the musical's Broadway revival on 9 February 2017 at the Palace Theatre.