[2] Her voice has appeared as backup vocals for artists such as Kings of Leon, the Good, the Bad & the Queen, Razorlight, Boy George and the Spice Girls, as the featured vocalist on big screen productions such as Dark City, and more recently as the singer and songwriter for a series of successful dance projects.

In 1998, composer Trevor Jones asked Kelsey to perform on the soundtrack to sci-fi cult film Dark City.

[4] During that same year, she appeared in the opening scenes of the horror movie Long Time Dead in which she participates in a ouija board séance just before dying a horrific death.

In 2006, Kelsey was approached by dance producer TTLC, also known as TDR (Tom de Ridder), to collaborate on electro track "Never Ever".

Kelsey also co-wrote Virgin Records's Lost Witness singles "Home" and "Coming Down", performed by Tiff Lacey.

A collaboration, "Wicked World", with Dutch production duo Hardsoul resulted in the track being picked up by Fedde Le Grande to remix for his debut album, Sessions, released on Ministry of Sound in 2007.

[7] In July 2016 she was awarded the Gerry Fowler prize by Middlesex University, for outstanding work in her studies and chosen field.