The group was formed in Liverpool in 1998 by Andy McCluskey from Orchestral Manoeuvres in the Dark. They are best known for doing "Eternal Flame," "Whole Again," and "Cradle," The members included Liz McClarnon, Natasha Hamilton, Kerry Katona, Jenny Frost, and Heidi Range (the latter two were not members of Atomic Kitten during the production of Thomas and the Magic Railroad, so did not play a part in the film's soundtrack).
They split up in 2004, but reunited in 2012.
- Liz McClarnon (1998-2004; 2012-present)
- Kerry Katona (1998-2001; 2012-2017)
- Heidi Range (1998-1999)
- Natasha Hamilton (1999-2004; 2012-present)
- Jenny Frost (2001-2004)
- Michelle Heaton (2013-present; International tours only)
- The Locomotion (performed)
- Member Natasha Hamilton used to be Mark Moraghan's singing partner.