"When I Lost You" is the debut single of English singer-songwriter Sarah Whatmore, written and produced by Richard Stannard.

[1] The song was originally due to be included on her debut album; however, her record company decided to pull the album.

The song was originally written for Kylie Minogue's album Fever (2001).

[2] The single was released on CD on 9 September 2002 in the United Kingdom.

In Australia, the song was released on 10 March 2003 and made a brief appearance on the ARIA Singles Chart, peaking at number 49 in May 2003.