Contestant Abbey Jordan, whose mother-and-daughter act failed to impress judges Dixon, David Walliams and Simon Cowell, slammed the former Mis-Teeq star's singing abilities on the microblogging site.
Jordan told the judge: "I'm the girl out of 'like mother like daughter' at auditions today, before you slag of my mums singing? Listen to yourself!"
Dixon tweeted back: "i was lovely 2 u yesterday! when you've grown up, sorted out ya attitude and sold some records come back and talk to me :) xxx"
Meanwhile, the young reject - who names her inspiration as TOWIE star Amy Childs - also called for Piers Morgan's return to the judging panel in place of Walliams.
She added: "David Walliams, I used to find you really funny! But in person? Not so funny. Give up Britain's Got Talent. Bring back Piers Morgan."
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