diff --git a/core/src/main/java/com/spotify/metrics/core/SemanticMetricDistribution.java b/core/src/main/java/com/spotify/metrics/core/SemanticMetricDistribution.java
index c45f453..5d45b2b 100644
--- a/core/src/main/java/com/spotify/metrics/core/SemanticMetricDistribution.java
+++ b/core/src/main/java/com/spotify/metrics/core/SemanticMetricDistribution.java
@@ -75,7 +75,7 @@ public ByteString getValueAndFlush() {
 
 
     @Override
-    public long getCount() {
+    public synchronized long getCount() {
         return distRef.get().size();
     }