diff --git a/headers/os/midi/MidiPort.h b/headers/os/midi/MidiPort.h
index 2c792e68aa..634c24e622 100644
--- a/headers/os/midi/MidiPort.h
+++ b/headers/os/midi/MidiPort.h
@@ -4,6 +4,8 @@
 
 #include <Midi.h>
 
+namespace BPrivate { class BMidiPortGlue; }
+
 class BMidiPort : public BMidi 
 {
 public:
@@ -59,7 +61,7 @@ private:
 
 	typedef BMidi super;
 
-	friend class BMidiPortGlue;
+	friend class BPrivate::BMidiPortGlue;
 
 	virtual void _ReservedMidiPort1();
 	virtual void _ReservedMidiPort2();
diff --git a/src/kits/midi/Midi.cpp b/src/kits/midi/Midi.cpp
index 59501d20d3..32796ed33c 100644
--- a/src/kits/midi/Midi.cpp
+++ b/src/kits/midi/Midi.cpp
@@ -30,6 +30,8 @@
 #include "MidiGlue.h"
 #include "debug.h"
 
+using namespace BPrivate;
+
 //------------------------------------------------------------------------------
 
 status_t _run_thread(void* data)
diff --git a/src/kits/midi/MidiGlue.cpp b/src/kits/midi/MidiGlue.cpp
index daffd9b2a9..68859106b7 100644
--- a/src/kits/midi/MidiGlue.cpp
+++ b/src/kits/midi/MidiGlue.cpp
@@ -25,6 +25,8 @@
 #include "MidiGlue.h"
 #include "MidiPort.h"
 
+using namespace BPrivate;
+
 //------------------------------------------------------------------------------
 
 BMidiGlue::BMidiGlue(BMidi* midiObject_, const char* name)
diff --git a/src/kits/midi/MidiGlue.h b/src/kits/midi/MidiGlue.h
index c8b8b055db..5cf678961b 100644
--- a/src/kits/midi/MidiGlue.h
+++ b/src/kits/midi/MidiGlue.h
@@ -29,6 +29,8 @@
 #define MAKE_TIME(t)    (t / (bigtime_t)1000)
 #define MAKE_BIGTIME(t) (t * (bigtime_t)1000)
 
+namespace BPrivate {
+
 class BMidiGlue: public BMidiLocalConsumer
 {
 public:
@@ -115,4 +117,6 @@ private:
 	BMidiPort* midiObject;
 };
 
+} // namespace BPrivate
+
 #endif // _MIDI_GLUE_H
diff --git a/src/kits/midi/MidiPort.cpp b/src/kits/midi/MidiPort.cpp
index cd011a2a47..28c8ea2c2a 100644
--- a/src/kits/midi/MidiPort.cpp
+++ b/src/kits/midi/MidiPort.cpp
@@ -29,6 +29,8 @@
 #include "MidiPort.h"
 #include "MidiGlue.h"
 
+using namespace BPrivate;
+
 //------------------------------------------------------------------------------
 
 BMidiPort::BMidiPort(const char* name)