The singer made her exit following a breakdown in communication and lack of trust with bandmates. Sugababes' record company has confirmed that another member Amelle Berrabah, who had quit the group last week over rows with Keisha will be back.
Keisha posted a Tweet mentioning it wasn"t her decision to leave the band: "I've had a great time and achieved more then I ever thought I would. Although it was not my choice to leave, it's time to enter a new chapter in my life."
She also dismissed reports that she had bullied Amelle and forced her out of the group.
She said: "There were no arguments, bullying or anything of the sort that led to this. Sometimes a breakdown in communication and lack of trust can result in many different things. I have nothing but positive things to say about the girls and I wish them the best of luck."
The beauty also thanked her fans for loving her.
She added: "I want to thank the Sugababes fans and my fans for all your support and all who have never judged me, but accepted me for who I am. I have a great family and friends who are behind me 100 per cent. I'm now going out into this world on my own. Although I'm nervous, I'm still very excited on what lies ahead."
Sugababes' record company released a statement saying: "Keisha will continue to record for Island Records as a solo artist."