diff --git a/src/probabilistic/HyperLogLog.h b/src/probabilistic/HyperLogLog.h
index 0a7ea6ac2f..f9920ab2a8 100644
--- a/src/probabilistic/HyperLogLog.h
+++ b/src/probabilistic/HyperLogLog.h
@@ -18,7 +18,7 @@ namespace probabilistic {
 
 
 class CardinalityCounter {
- friend class CardinalityVal;
+ friend class ::CardinalityVal;
 
  private:
   /*