diff --git a/hibernate-core/src/main/java/org/hibernate/persister/entity/DiscriminatorType.java b/hibernate-core/src/main/java/org/hibernate/persister/entity/DiscriminatorType.java
index 9a391614a6..05039e1e14 100644
--- a/hibernate-core/src/main/java/org/hibernate/persister/entity/DiscriminatorType.java
+++ b/hibernate-core/src/main/java/org/hibernate/persister/entity/DiscriminatorType.java
@@ -109,9 +109,9 @@ public class DiscriminatorType extends AbstractType {
 			Object value,
 			int index,
 			SessionImplementor session) throws HibernateException, SQLException {
-		throw new UnsupportedOperationException(
-				"At the moment this type is not the one actually used to map the discriminator."
-		);
+		String entityName = session.getFactory().getClassMetadata((Class) value).getEntityName();
+		Loadable entityPersister = (Loadable) session.getFactory().getEntityPersister(entityName);
+		underlyingType.nullSafeSet(st, entityPersister.getDiscriminatorValue(), index, session);
 	}
 
 	public String toLoggableString(Object value, SessionFactoryImplementor factory) throws HibernateException {