Taking to Twitter, the Coronation Street actress wrote angrily: "This is NOT my daughter's Facebook!
"Some sick, sick people out there."
Accompanying the message was a screen grab of the fake online account, which has been set up as if made by Kym's eldest daughter, aspiring musician Emily Mae Cunliffe.
She then added two hours later: "Again another account that is not my daughters Facebook and whoever this is has stolen a photo that I have not made public."
Kym, 38, found solace in her fans, who were quick to offer the former Hear'Say singer their support.
One wrote: "Despicable behaviour from attention seekers."
KYM MARSH SLAMMED BY HEALTH EXPERTS FOR 'SMOKING WITH 16-YEAR-OLD DAUGHTER'
Another added: "Probably not sick Kim just plain old jealously x."
It appears to have been taken down from the social media site since.
Kym recently revealed that 16-year-old Emily, her daughter with ex-partner David Cunliffe, is still in touch with her ex-stepfather Jack Ryder - five years after he and Kym divorced.
She told Manchester based radio station Key 103 in July: "To be honest we’re not really in contact but nothing’s bad between us, we didn’t leave things in a bad way."
Kym added: "We don’t have any contact but he is in contact with my daughter, Emily."
Kym is now dating personal trainer Dan Hooper.
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