diff --git a/include/verilated_types.h b/include/verilated_types.h
index 0a92725a9e..54d652f70c 100644
--- a/include/verilated_types.h
+++ b/include/verilated_types.h
@@ -1685,6 +1685,10 @@ class VlClassRef final {
 
 template <typename T, typename U>
 static inline bool VL_CAST_DYNAMIC(VlClassRef<T> in, VlClassRef<U>& outr) {
+    if (!in) {
+        outr = VlNull{};
+        return true;
+    }
     VlClassRef<U> casted = in.template dynamicCast<U>();
     if (VL_LIKELY(casted)) {
         outr = casted;