diff --git a/src/class.c b/src/class.c
index 7a81c92..6d0db9c 100644
--- a/src/class.c
+++ b/src/class.c
@@ -81,15 +81,15 @@ int uopz_find_mock(zend_string *clazz, zend_object **object, zend_class_entry **
 	}
 
 	if (Z_TYPE_P(found) == IS_STRING) {
-		*mock = zend_lookup_class(Z_STR_P(found));
+		*mock = zend_fetch_class_by_name(Z_STR_P(found), NULL, ZEND_FETCH_CLASS_EXCEPTION);
+		return *mock ? SUCCESS : FAILURE;
 	} else {
 		*mock = Z_OBJCE_P(found);
 		if (object) {
 			*object = Z_OBJ_P(found);
 		}
+		return SUCCESS;
 	}
-
-	return SUCCESS;
 } /* }}} */
 
 /* {{{ */
diff --git a/src/handlers.c b/src/handlers.c
index fe4f1e7..36cd33d 100644
--- a/src/handlers.c
+++ b/src/handlers.c
@@ -279,10 +279,12 @@ int uopz_vm_new(UOPZ_OPCODE_HANDLER_ARGS) { /* {{{ */
 
 	if (opline->op1_type == IS_CONST) {
 		if (uopz_find_mock(Z_STR_P(EX_CONSTANT(opline->op1)), &obj, &ce) != SUCCESS) {
-			ce = zend_fetch_class_by_name(
-				Z_STR_P(EX_CONSTANT(opline->op1)),
-				Z_STR_P(EX_CONSTANT(opline->op1) + 1),
-				ZEND_FETCH_CLASS_DEFAULT | ZEND_FETCH_CLASS_EXCEPTION);
+			if (!EG(exception)) {
+				ce = zend_fetch_class_by_name(
+					Z_STR_P(EX_CONSTANT(opline->op1)),
+					Z_STR_P(EX_CONSTANT(opline->op1) + 1),
+					ZEND_FETCH_CLASS_DEFAULT | ZEND_FETCH_CLASS_EXCEPTION);
+			}
 
 			if (ce == NULL) {
 				ZVAL_UNDEF(EX_VAR(opline->result.var));
diff --git a/tests/004.phpt b/tests/004.phpt
index e942278..b7779b2 100644
--- a/tests/004.phpt
+++ b/tests/004.phpt
@@ -29,6 +29,14 @@ uopz_unset_mock(Foo::class);
 uopz_set_mock(Bar::class, new Foo);
 
 var_dump(new Bar());
+
+uopz_set_mock(Foo::class, DoesntExist::class);
+try {
+    var_dump(new Foo);
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
 ?>
 --EXPECTF--
 object(Bar)#%d (0) {
@@ -37,3 +45,4 @@ int(1)
 int(-1)
 object(Foo)#%d (0) {
 }
+Class "DoesntExist" not found