The ‘Coronation Street’ actress, 41, who is mum to Polly, six, Emilie, 19, David, 21, and Archie, who passed away after he was born 19 weeks early, said the account was using photos of Polly without her permission.
“The fake account of my six-year-old Polly Connor has blocked me,” she tweeted on Sunday 30 July.
“You are using photos of my little girl you strange, strange person.”
The fake account uses the surname of Marsh’s ‘Coronation Street’ character, Michelle Connor. There is also a fake account set up, acting as the fictional character Michelle.
At the time of writing, the account pretending to be Polly was still active.
Marsh tweeted: “Something needs to be done about people making fake accounts on social media. Why would anyone make a fake account of a six-year-old?
The fake account uses a photo of Polly as the profile picture, and photos of Marsh with her daughter Polly as the cover photos.
Carolyn Bunting, general manager of Internet Matters, an organisation designed to help parents keep their children safe online, gave the following advice on identity theft:
“Kym’s story reminds us of the importance of being vigilant online, especially on social media.
“Kym and her followers spotted the account and reported it to Twitter, which is essential in helping social media organisations identify irresponsible users.
“If you are worried about online identity theft, you should flag up to the social media network and report the account to the police.
“For more information on getting to grips with reporting on social media visit internetmatters.org.”
HuffPost UK has contacted Twitter for comment and will update this piece upon their response.