She said: "They could call themselves The Real Sugababes. It would knock the current Sugababes out of the water.
"If one wasn't up for it, I could be the blonde one."
Despite recent speculation, Keisha has insisted she is not planning a reunion with Mutya and Siobhan, who formed the trio in 1998.
Her spokesperson said: "Keisha is definitely 100 per cent not going to be involved in any kind of Sugababes reformation. Keisha has solo projects that she's working on which will be out next year."
Keisha's replacement in the current line-up of the group, Jade Ewen, recently said she is terrified of meeting the singer.
Jade, 21, said: "I haven't met her yet. I'm quite scared. I'm sure she wouldn't do anything to me..."
Siobhan was the first of the Sugababes to leave the group, departing in 2001 to be replaced by Heidi Range, while Amelle Berrabah joined the group in 2005 to replace Mutya.