diff --git a/compile.c b/compile.c
index fd8c26cad5a1b7..88b6719b62debe 100644
--- a/compile.c
+++ b/compile.c
@@ -1442,7 +1442,7 @@ new_insn_body(rb_iseq_t *iseq, const NODE *const line_node, enum ruby_vminsn_typ
 }
 
 static const struct rb_callinfo *
-new_callinfo(rb_iseq_t *iseq, ID mid, int argc, unsigned int flag, struct rb_callinfo_kwarg *kw_arg, int has_blockiseq)
+new_callinfo(rb_iseq_t *iseq, ID mid, int argc, unsigned int flag, const struct rb_callinfo_kwarg *kw_arg, int has_blockiseq)
 {
     VM_ASSERT(argc >= 0);
 
@@ -3933,12 +3933,16 @@ iseq_specialized_instruction(rb_iseq_t *iseq, INSN *iobj)
             switch (vm_ci_mid(ci)) {
               case idNew:
                 iobj->insn_id = BIN(opt_new);
+                fprintf(stderr, "operand_size = %d\n", iobj->operand_size);
                 // TODO: add a second call_data for `#initialize`
+                //
+                // const struct rb_callinfo * new_ci = (struct rb_callinfo *)iobj->operands[0];
+                iobj->operands[1] = (VALUE)new_callinfo(iseq, idInitialize, vm_ci_argc(ci), vm_ci_flag(ci) | VM_CALL_FCALL, vm_ci_kwarg(ci), FALSE);
                 break;
               default:
                 iobj->insn_id = BIN(opt_send_without_block);
+                iobj->operand_size = insn_len(iobj->insn_id) - 1;
             }
-            iobj->operand_size = insn_len(iobj->insn_id) - 1;
         }
     }
 #undef SP_INSN
diff --git a/defs/id.def b/defs/id.def
index 2ddde7be70702a..f9912dd9110d5e 100644
--- a/defs/id.def
+++ b/defs/id.def
@@ -5,6 +5,7 @@ firstline, predefined = __LINE__+1, %[\
   hash
   freeze
   nil?
+  new
   inspect
   intern
   object_id
diff --git a/insns.def b/insns.def
index 124448e30cebea..fa1f417b8dbfc9 100644
--- a/insns.def
+++ b/insns.def
@@ -831,7 +831,7 @@ opt_send_without_block
 /* Invoke constructor */
 DEFINE_INSN
 opt_new
-(CALL_DATA cd)
+(CALL_DATA cd, CALL_DATA cd_initialize)
 (...)
 (VALUE val)
 // attr bool handles_sp = true;
@@ -842,20 +842,24 @@ opt_new
 
     val = vm_opt_new_alloc(GET_ISEQ(), recv, cd);
     if (val != Qundef) {
+        TOPN(vm_ci_argc(cd->ci)) = val;
         fprintf(stderr, "opt!\n");
-        // TODO: call initialize (need a second CALL_DATA).
+        if (vm_sendish(ec, GET_CFP(), cd_initialize, VM_BLOCK_HANDLER_NONE, mexp_search_method) == Qundef) {
+            val = Qundef;
+        }
     }
-    else {
+
+    if (val == Qundef) {
         fprintf(stderr, "de-opt!\n");
-    }
 
-    VALUE bh = VM_BLOCK_HANDLER_NONE;
-    val = vm_sendish(ec, GET_CFP(), cd, bh, mexp_search_method);
-    JIT_EXEC(ec, val);
+        VALUE bh = VM_BLOCK_HANDLER_NONE;
+        val = vm_sendish(ec, GET_CFP(), cd, bh, mexp_search_method);
+        JIT_EXEC(ec, val);
 
-    if (val == Qundef) {
-        RESTORE_REGS();
-        NEXT_INSN();
+        if (val == Qundef) {
+            RESTORE_REGS();
+            NEXT_INSN();
+        }
     }
 }