The 33-year-old, who enjoyed eleven Top 5 singles with the pop band, will perform a track from her upcoming solo album at the Royal Albert Hall in London.
"It's been marinating for a while and now it's just about ready! Yes I'm very excited to announce I will be performing a track from my solo album for the very first time, no S Club 7 - just me! " she wrote on her blog.
Barrett has posted three songs on her MySpace page called 'I'll Be Your Woman', 'Blow My Mind' and 'Satisfy Me'.
S Club 7 stars Jo O’Meara, Bradley McIntosh and Paul Cattermole reformed last year as a three-piece and performed a number of live dates across the UK.
Peter Andre and Mutya Buena were recently confirmed to perform a collaboration at the event, which aims to raise money to help protect wild animals and alleviate the suffering of those in captivity.