diff --git a/headers/os/midi2/MidiConsumer.h b/headers/os/midi2/MidiConsumer.h
index c4e0ab39a7..0f5b289aa3 100644
--- a/headers/os/midi2/MidiConsumer.h
+++ b/headers/os/midi2/MidiConsumer.h
@@ -4,6 +4,8 @@
 
 #include <MidiEndpoint.h>
 
+namespace BPrivate { class BMidiRosterLooper; }
+
 class BMidiConsumer : public BMidiEndpoint
 {
 public:
@@ -15,7 +17,7 @@ private:
 	friend class BMidiLocalConsumer;
 	friend class BMidiLocalProducer;
 	friend class BMidiRoster;
-	friend class BMidiRosterLooper;
+	friend class BPrivate::BMidiRosterLooper;
 	
 	BMidiConsumer(const char* name = NULL);	
 	virtual ~BMidiConsumer();
diff --git a/headers/os/midi2/MidiEndpoint.h b/headers/os/midi2/MidiEndpoint.h
index 0ac72ccd05..f0c7ea2c88 100644
--- a/headers/os/midi2/MidiEndpoint.h
+++ b/headers/os/midi2/MidiEndpoint.h
@@ -10,6 +10,8 @@
 class BMidiProducer;
 class BMidiConsumer;
 
+namespace BPrivate { class BMidiRosterLooper; }
+
 class BMidiEndpoint 
 {
 public:
@@ -42,7 +44,7 @@ private:
 	friend class BMidiLocalProducer;
 	friend class BMidiProducer;
 	friend class BMidiRoster;
-	friend class BMidiRosterLooper;
+	friend class BPrivate::BMidiRosterLooper;
 	
 	BMidiEndpoint(const char* name);
 	virtual	~BMidiEndpoint();
diff --git a/headers/os/midi2/MidiProducer.h b/headers/os/midi2/MidiProducer.h
index b367393bbd..bccff87516 100644
--- a/headers/os/midi2/MidiProducer.h
+++ b/headers/os/midi2/MidiProducer.h
@@ -7,6 +7,8 @@
 
 class BList;
 
+namespace BPrivate { class BMidiRosterLooper; }
+
 class BMidiProducer : public BMidiEndpoint
 {
 public:
@@ -20,7 +22,7 @@ private:
 
 	friend class BMidiLocalProducer;
 	friend class BMidiRoster;
-	friend class BMidiRosterLooper;
+	friend class BPrivate::BMidiRosterLooper;
 	
 	BMidiProducer(const char* name = NULL);	
 	virtual ~BMidiProducer();
diff --git a/headers/os/midi2/MidiRoster.h b/headers/os/midi2/MidiRoster.h
index 4e1163c43a..4cae35a4cb 100644
--- a/headers/os/midi2/MidiRoster.h
+++ b/headers/os/midi2/MidiRoster.h
@@ -22,6 +22,12 @@ enum BMidiOp
 class BMidiProducer;
 class BMidiConsumer;
 
+namespace BPrivate
+{
+	class BMidiRosterLooper;
+	struct BMidiRosterKiller;
+}
+
 class BMidiRoster
 {
 public:
@@ -49,8 +55,8 @@ private:
 	friend class BMidiLocalProducer;
 	friend class BMidiLocalConsumer;
 	friend class BMidiProducer;
-	friend class BMidiRosterKiller;
-	friend class BMidiRosterLooper;
+	friend class BPrivate::BMidiRosterLooper;
+	friend struct BPrivate::BMidiRosterKiller;
 
 	BMidiRoster();
 	virtual ~BMidiRoster();
@@ -69,7 +75,7 @@ private:
 
 	status_t SendRequest(BMessage*, BMessage*);
 
-	BMidiRosterLooper* looper;
+	BPrivate::BMidiRosterLooper* looper;
 	BMessenger* server;
 
 	uint32 _reserved[16];