diff --git a/core/extension/gdextension_interface.cpp b/core/extension/gdextension_interface.cpp
index c886c2f3868..4ab9849404e 100644
--- a/core/extension/gdextension_interface.cpp
+++ b/core/extension/gdextension_interface.cpp
@@ -1584,6 +1584,15 @@ static GDExtensionScriptInstancePtr gdextension_object_get_script_instance(GDExt
 	return script_instance_extension->instance;
 }
 
+static void gdextension_object_set_script_instance(GDExtensionObjectPtr p_object, GDExtensionScriptInstancePtr p_script_instance) {
+	ERR_FAIL_NULL(p_object);
+
+	Object *o = (Object *)p_object;
+	ScriptInstance *script_instance = (ScriptInstanceExtension *)p_script_instance;
+
+	o->set_script_instance(script_instance);
+}
+
 #ifndef DISABLE_DEPRECATED
 static void gdextension_callable_custom_create(GDExtensionUninitializedTypePtr r_callable, GDExtensionCallableCustomInfo *p_custom_callable_info) {
 	memnew_placement(r_callable, Callable(memnew(CallableCustomExtension(p_custom_callable_info))));
@@ -1824,6 +1833,7 @@ void gdextension_setup_interface() {
 	REGISTER_INTERFACE_FUNC(placeholder_script_instance_create);
 	REGISTER_INTERFACE_FUNC(placeholder_script_instance_update);
 	REGISTER_INTERFACE_FUNC(object_get_script_instance);
+	REGISTER_INTERFACE_FUNC(object_set_script_instance);
 #ifndef DISABLE_DEPRECATED
 	REGISTER_INTERFACE_FUNC(callable_custom_create);
 #endif // DISABLE_DEPRECATED
diff --git a/core/extension/gdextension_interface.h b/core/extension/gdextension_interface.h
index 27771430bda..1bf54199b3b 100644
--- a/core/extension/gdextension_interface.h
+++ b/core/extension/gdextension_interface.h
@@ -2743,6 +2743,17 @@ typedef void (*GDExtensionInterfacePlaceHolderScriptInstanceUpdate)(GDExtensionS
  */
 typedef GDExtensionScriptInstanceDataPtr (*GDExtensionInterfaceObjectGetScriptInstance)(GDExtensionConstObjectPtr p_object, GDExtensionObjectPtr p_language);
 
+/**
+ * @name object_set_script_instance
+ * @since 4.5
+ *
+ * Set the script instance data attached to this object.
+ *
+ * @param p_object A pointer to the Object.
+ * @param p_script_instance A pointer to the script instance data to attach to this object.
+ */
+typedef void (*GDExtensionInterfaceObjectSetScriptInstance)(GDExtensionObjectPtr p_object, GDExtensionScriptInstanceDataPtr p_script_instance);
+
 /* INTERFACE: Callable */
 
 /**