diff --git a/hibernate-core/src/main/java/org/hibernate/type/EntityType.java b/hibernate-core/src/main/java/org/hibernate/type/EntityType.java
index f7f2f0eeec..e09f6ca6b6 100644
--- a/hibernate-core/src/main/java/org/hibernate/type/EntityType.java
+++ b/hibernate-core/src/main/java/org/hibernate/type/EntityType.java
@@ -346,7 +346,7 @@ public abstract class EntityType extends AbstractType implements AssociationType
 			else {
 				Object id = getIdentifier( original, session );
 				if ( id == null ) {
-					throw new AssertionFailure("non-transient entity has a null id");
+					throw new AssertionFailure("non-transient entity has a null id: "+original.getClass().getName());
 				}
 				id = getIdentifierOrUniqueKeyType( session.getFactory() )
 						.replace(id, null, session, owner, copyCache);