Tyrese -- Blasts Comedian ... You're Done in This Town!

Tyrese went nuclear on the comedian who dared to drop some ridiculous casting couch accusations -- and safe to say, the comedian will NOT be laughing at this videotaped response ... but you will ... 'cause it's awesome.

The comedian, Spanky Hayes, claims he was beaten out for the lead in "Baby Boy" because Tyrese performed sexual favors for director John Singleton. Tyrese recorded a rebuttal to Spanky, and the hysterical theme of it is ... "You know you done f**ked up, right?"

Just for good measure -- Tyrese shot the whole comeback while walking around his mansion in a fur robe and smoking a cigar. Spanky, you've been served.