diff --git a/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php b/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
index 882694d..74d921f 100644
--- a/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
+++ b/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
@@ -6,6 +6,7 @@
 use Drupal\Core\Entity\Query\QueryException;
 use Drupal\Core\Entity\Sql\SqlEntityStorageInterface;
 use Drupal\Core\Entity\Sql\TableMappingInterface;
+use Drupal\Core\Entity\TypedData\EntityDataDefinitionInterface;
 use Drupal\Core\TypedData\DataReferenceDefinitionInterface;
 
 /**
@@ -264,9 +265,9 @@ public function addField($field, $type, $langcode) {
         if (isset($propertyDefinitions[$relationship_specifier]) && $propertyDefinitions[$relationship_specifier] instanceof DataReferenceDefinitionInterface) {
           // If it is, use the entity type if specified already, otherwise use
           // the definition.
-          if (!$entity_type_id) {
-            $entity_type_id = $propertyDefinitions[$relationship_specifier]->getTargetDefinition()
-              ->getEntityTypeId();
+          $target_definition = $propertyDefinitions[$relationship_specifier]->getTargetDefinition();
+          if (!$entity_type_id &&  $target_definition instanceof EntityDataDefinitionInterface) {
+            $entity_type_id = $target_definition->getEntityTypeId();
           }
           $entity_type = $this->entityManager->getDefinition($entity_type_id);
           $field_storage_definitions = $this->entityManager->getFieldStorageDefinitions($entity_type_id);