1 files changed, 2 insertions, 0 deletions
diff --git a/include/grpc++/impl/codegen/call_hook.h b/include/grpc++/impl/codegen/call_hook.h
index d026cc8b58..44e9de220e 100644
--- a/include/grpc++/impl/codegen/call_hook.h
+++ b/include/grpc++/impl/codegen/call_hook.h
@@ -21,6 +21,7 @@
 
 namespace grpc {
 
+namespace internal {
 class CallOpSetInterface;
 class Call;
 
@@ -31,6 +32,7 @@ class CallHook {
   virtual ~CallHook() {}
   virtual void PerformOpsOnCall(CallOpSetInterface* ops, Call* call) = 0;
 };
+}  // namespace internal
 
 }  // namespace grpc