"I judge people on how they perform in the ring and I see nothing in his performances, his mouth is interesting but his performances aren't."
Calzaghe has, like Froch, enjoyed a superb 2008 as he beat American pound-for-pound greats Bernard Hopkins and Roy Jones Jr in the United States.
Although he is considering retirement, American TV giants HBO have told the 36-year-old they are willing to come to the UK if he wants a career finale in Cardiff next summer.
However, Calzaghe said HBO would "not be interested" in Froch.
But Froch reacted angrily to Calzaghe's claims and said: "The way he talks and about me and Jean Pascal not being world class is laughable, it's just ridiculous.
"He fought Bernard Hopkins and Roy Jones Jr but he has forgotten that Hopkins is 43 and well, well past his best.
"He got beat against Hopkins in my opinion and many other's peoples opinion, including one of the fight judges because it was a split decision victory.
"Roy Jones Jr is 39-years-old and I would have taken more pleasure refusing a fight with Jones because he should not be fighting the guy.
"And his comments that he'll knock me out? Joe Calzaghe doesn't knock anyone out these days, he slaps for 12 rounds.
"And he got decked against Hopkins and Jones in the first round, if I did that I wouldn't let him off the hook.
"But without getting into a slagging match and looking like I'm over critical, silly and horrible but he must be a little bit thick, because his comments are absolutely ridiculous so he must be a little bit stupid."
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