diff --git a/libs/ardour/ardour/vst3_plugin.h b/libs/ardour/ardour/vst3_plugin.h
index 169aa8abb2..5b31fbfc6c 100644
--- a/libs/ardour/ardour/vst3_plugin.h
+++ b/libs/ardour/ardour/vst3_plugin.h
@@ -351,8 +351,6 @@ public:
 #endif
 	void update_contoller_param ();
 
-	bool configure_io (ChanCount in, ChanCount out);
-
 	PBD::Signal2<void, int, int> OnResizeView;
 
 private:
diff --git a/libs/ardour/vst3_plugin.cc b/libs/ardour/vst3_plugin.cc
index 5d03c4f239..f2d6dbabdd 100644
--- a/libs/ardour/vst3_plugin.cc
+++ b/libs/ardour/vst3_plugin.cc
@@ -546,12 +546,6 @@ VST3Plugin::plugin_latency () const
 	return _plug->plugin_latency ();
 }
 
-bool
-VST3Plugin::configure_io (ChanCount in, ChanCount out)
-{
-	return Plugin::configure_io (in, out);
-}
-
 void
 VST3Plugin::add_slave (boost::shared_ptr<Plugin> p, bool rt)
 {