Killer in a Red Dress (2018)

Christa Bright is an aspiring personal stylist who has an instant connection with new client Kat Niven, a shy woman who needs help gaining confidence. But when Kat's admiration for Christa turns into plain obsession, Christa begins to get suspicious. She soon discovers that Kat is her fiance Jack's ex-girlfriend and she's trying to become Christa in a demented ploy to win Jack back for good.