Last week, viewers saw a crazed Becky McDonald smash up Tracy Barlow's living room with a sledgehammer, wrongly believing that her arch-nemesis had reported her to social services for buying nephew Max.
Discussing the shock scenes, Kelly told Scotland's Sunday Mail newspaper: "My brothers laugh their heads off when they see me like that. I am tough in my mind, very strong-willed, but when it comes to physicality, I'm a bit pathetic.
"My shopping bag bangs into my shin and it bruises. So it takes a lot for me, and it always has done, to make Becky look like a street fighter. I do find those scenes full on."
She continued: "There was Ken and Deirdre Barlow, Tracy and Steve. I thought to myself, 'I've got four Coronation Street icons in this room - and they have given me a sledgehammer'. You can have all the health and safety you want but I thought, 'I better not mess this up and bash somebody!'
"It took us six hours to shoot that scene. I did swear a few times after those takes but what a thrill. I do love all that. The further removed from me, Katherine Kelly, the more of a buzz it gives me."
Tonight's Coronation Street double bill sees Becky and Steve struggle to get their marriage back on track in the aftermath of Max being taken away.
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