Kim and Denise (Diane Parish) are left stunned over the festive season when they are sent a USB stick which contains a recording of Phil confessing to his role in the death of Kevin Wicks.
The USB stick is placed in a mysterious package which ends up under Denise's Christmas tree - seemingly the latest stunt pulled by Phil's stalker.
Empson, who plays Kim, told Inside Soap: "When all the information about Kevin Wicks and Phil blows up, it comes out of nowhere for the Fox girls. Kevin's death was way before Kim's time, so she's bewildered by the whole thing. They wonder why someone would tell them about such a thing on Christmas Day."
However, she continued: "Kim knows no fear. It might be Phil, but she's not afraid to take him on. The Mitchells think that they're the big guns in the Square - but as far as Kim's concerned, the Fox family are the same.
"They might not have the same numbers as the Mitchells, but they won't shy away from a fight."
Empson added that she gets on much better with Steve McFadden, who plays Phil, once the cameras stop rolling.
"He's such a great actor because he's not like his character Phil at all," she said. "He's so lovely."
EastEnders airs Denise's shock over Kevin on December 25 at 9pm on BBC One.
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Watch Kim's EastEnders character trail below: