The star, 36, will perform songs from musical theatre as well as reworked Girls Aloud hits at West End cabaret club Crazy Coqs.
Walsh, who appeared in Shrek The Musical, trained in musical theatre before finding fame with the girl group, who split after their first reunion in 2013.
She has been spending more time away from the spotlight to look after her sons Bobby, three, and Cole, 18 months, with husband Justin Scott.
Her former bandmates could be at her shows. She said: “I’m going to invite them all — it will be weird for them watching me on stage alone, so I wouldn’t be surprised if any of them came up on stage if they found the urge. It could be a mini-reunion!”
Asked about them reforming, she said: “If it comes along at the right time I would definitely be up for it.
"The more years you spend apart, the more nostalgic you become, and you miss each other.”
Kimberley Walsh is at Crazy Coqs from July 23 to 29 (brasseriezedel.com/reservations).