Comedian Katt Williams has been ordered to fork over $577,929 to an Atlanta record producer — after Katt allegedly sicked his attack dog on the other man’s pet canine … nearly killing the animal.

The producer, Merion Joseph Powers, had sued Katt in Atlanta — claiming the comic racked up a $28k bill in his studio, but refused to pay the debt … and when he pressed Williams for the dough, Katt paid him a visit with his attack dog in tow.

Powers alleged Katt — in an effort to intimidate him into backing off the debt — showed up to his studio with an attack dog and gave it a “verbal attack signal” to go after Merion’s dog … which suffered “substantial and nearly life-threatening injuries.”

But when Merion had his day in court — the judge ruled in his favor … and ordered Katt to pay the man a whopping $577k.

Calls to Katt’s reps were not returned.

Via Tmz.com