Confirming this news over the weekend, the singer announced her departure from the band after 26 years via social media.
Hamilton was an original member of Atomic Kitten alongside singers Liz McClarnon and Kerry Katona, joining the band in 1998. The band are renowned for their 2000 hit, 'Whole Again'.
Taking to Instagram, Hamilton wrote: “Twenty-six incredible years, writing so many wonderful chapters, but now the time has come for me to close the book on this one".
She continued: “The ride hasn’t always been smooth but I wouldn’t change a single thing. I’ve laughed and cried many a time with the girls, experienced so many surreal moments and been blessed with a career spanning 26 years – it’s been incredible and something I will always cherish".
“Since 2013 myself and Liz have been on the nostalgia train, and we have performed non stop since then (apart from the global pandemic) where we came back even stronger, with more demand for our infectious pop songs".
“At the beginning of the year I didn’t know how to juggle being a Kitten, whilst also trying to break out as a solo artist, but I gave it a go and I have to say, it’s been tough", she added. “This Sunday marks my final Atomic Kitten gig for the foreseeable future. I will step down from all AK duties to concentrate on me and ventures new".
Natasha Hamilton also confirmed plans to release more solo music in the next few weeks, including her debut solo EP from her own record label, which she recently launched.
She also extended her best wishes to Liz McClarnon, wishing her “all the luck and love in the world".
McClarnon replied by commenting "Love you".
The last three decades have seen Atomic Kitten perform at several festivals, including the Eurovision Song Contest in Liverpool in May, as well as Pride earlier this year.
The band also released a reworked version of 'Whole Again', titled 'Southgate You're The One', in support of the England Football Team at the World Cup in Qatar.