Siobhán Emma Donaghy (born 14 June 1984) is an English singer-songwriter She was a founding member of girl group the Sugababes and Mutya Keisha Siobhan. Donaghy left Sugababes in 2001 following arguments and accusations in the band with Keisha Buchanan. Donaghy released her debut solo album on Revolution in Me on 23 September 2003 which contained three single releases. Donaghy released her second studio album Ghosts on 25 June 2007. Donaghy appeared in a remixed version of the hit stage show Rent Remixed for its 2007–2008 run playing the role of Mimi alongside Denise Van Outen.
On 20 July 2012, Donaghy and her former Sugababes bandmates, Buena and Buchanan confirmed their reunion. The original trio will not be able to release music under the name "Sugababes" as it is still being used by the current members of the band. They will instead release music under the new band name, Mutya Keisha Siobhan.