The actress plays Becky McDonald in the ITV1 soap, who will drunkenly smash into Tracy Barlow's living room with a sledgehammer and threaten to kill her in an upcoming plot.
Kelly will wear back support containing "spring-like metal stays" to protect her. It has been designed to be hidden under her clothes, The People reports.
Furthermore, a stunt expert has apparently been teaching the soap star - who recently insisted that she is staying on the show - how to safely use the weapon, while a medic will be on hand during the shoot.
"The scenes are so violent that the producers are genuinely worried that Katherine might hurt herself," a source said. "Becky is drunk and she is supposed to go totally ballistic.
"She needs to wield the hammer really aggressively. The producers know that she will put her heart and soul into it, so they are making her safety a priority."
It was recently reported that Becky will face fresh heartache when Max is taken into care.