Songfacts®:

• This is the main song from the theater musical Wicked, which has played to packed houses since its opening on both Broadway and in the West End in 2003. It is mostly a solo sung by the main character of the show, Elphaba (the Wicked Witch of the West) in the finale for the show's first act, but also features two small duets at the beginning and in the middle of the song between Elphaba and her friend Glinda, and a chorus part in the end in which the citizens of Oz sing. The song is sung by Elphaba after the Wizard of Oz reveals his true self to her and as a consequence, she promises to fight the Wizard with all of her power.
• The song was composed by Stephen Schwartz, originally recorded by Idina Menzel and Kristin Chenoweth on November 10, 2003, and released on December 16, 2003. After being performed on the BBC talent show television programme I'd Do Anything in 2008 the song charted at #60 on the official UK Singles chart.
• The song was performed by Lea Michele and Chris Colfer on the Fox musical drama show, Glee when their two characters competed for a lead role by singing this number. The resulting downloads took the song into both the UK and US Top 40 for the first time. Kristin Chenoweth had coincidentally previously charted in a guest starring role as a member of the Glee Cast when their version of "Alone" made #51 in the US and #47 in the UK.
• In 2009, 25 different singles from the Glee Cast charted on the Billboard Hot 100, the most by any artist since the Beatles had 31 songs in the chart in 1964.