diff --git a/velox/functions/lib/aggregates/CentralMomentsAggregatesBase.h b/velox/functions/lib/aggregates/CentralMomentsAggregatesBase.h
index d0bd97874715b..1e3035b0ccf3a 100644
--- a/velox/functions/lib/aggregates/CentralMomentsAggregatesBase.h
+++ b/velox/functions/lib/aggregates/CentralMomentsAggregatesBase.h
@@ -32,7 +32,7 @@ struct CentralMomentsIndices {
 constexpr CentralMomentsIndices kCentralMomentsIndices{0, 1, 2, 3, 4};
 
 struct CentralMomentsAccumulator {
-  double count() const {
+  int64_t count() const {
     return count_;
   }
 
@@ -83,6 +83,14 @@ struct CentralMomentsAccumulator {
     if (otherCount == 0) {
       return;
     }
+    if (count_ == 0) {
+      count_ = otherCount;
+      m1_ = otherM1;
+      m2_ = otherM2;
+      m3_ = otherM3;
+      m4_ = otherM4;
+      return;
+    }
 
     double oldCount = count();
     count_ += otherCount;