Siobhan McCarthy first appeared in the West End in the original production of Evita creating the role of the Mistress in 1978. Upon leaving she crossed the road to the Palace to play Mary Magdalene in Jesus Christ Superstar. When the production closed, she was asked to join the 'Wall Street Crash' a singing group, with which she toured Europe extensively for two years, as well as appearing on The Royal Command Performances and many television shows. In 1983 she returned to the Prince Edward to play the title role in Evita for a year. Then in 1984 created the role of Frankie Frayre in On Your Toes. During this time Siobhan has appeared three times on the very popular Bob Monkhouse show singing with the Harry Stoneham Band and also in the Night of 100 Stars.
(Note: Biography is from the original programme.)
After Elaine Paige left Chess, Siobhan McCarthy took over the role of Florence. In 1999, she returned to the star dressing room at the Prince Edward Theatre to play Donna Sheridan in MAMMA MIA!, a show with songs exclusively by Benny Anderson and Björn Ulvaeus from their 1970s days as the "B's" in the Swedish rock group ABBA.