diff --git a/src/google/protobuf/message_lite.h b/src/google/protobuf/message_lite.h
index 41a7789142..3d43397486 100644
--- a/src/google/protobuf/message_lite.h
+++ b/src/google/protobuf/message_lite.h
@@ -198,6 +198,10 @@ class PROTOBUF_EXPORT CachedSize {
     ABSL_DCHECK_NE(desired, 0);
     __atomic_store_n(&atom_, desired, __ATOMIC_RELAXED);
   }
+
+  void SetNoDefaultInstance(Scalar desired) const noexcept {
+    __atomic_store_n(&atom_, desired, __ATOMIC_RELAXED);
+  }
 #else
   CachedSize(const CachedSize& other) noexcept : atom_(other.Get()) {}
   CachedSize& operator=(const CachedSize& other) noexcept {
@@ -222,6 +226,10 @@ class PROTOBUF_EXPORT CachedSize {
     ABSL_DCHECK_NE(desired, 0);
     atom_.store(desired, std::memory_order_relaxed);
   }
+
+  void SetNoDefaultInstance(Scalar desired) const noexcept {
+    atom_.store(desired, std::memory_order_relaxed);
+  }
 #endif
 
  private: