diff --git a/src/include/distributed/multi_planner_utils.h b/src/include/distributed/multi_planner_utils.h
new file mode 100644
index 000000000..8d515db53
--- /dev/null
+++ b/src/include/distributed/multi_planner_utils.h
@@ -0,0 +1,22 @@
+/*
+ * multi_planner_utils.h
+ *
+ * This file contains functions helper functions for planning
+ * queries with colocated tables and subqueries.
+ *
+ * Copyright (c) 2017-2017, Citus Data, Inc.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef MULTI_PLANNER_UTILS_H
+#define MULTI_PLANNER_UTILS_H
+
+#include "distributed/multi_planner.h"
+
+
+extern bool AllRelationsJoinedOnPartitionKey(PlannerRestrictionContext *
+											 plannerRestrictionContext);
+
+
+#endif /* MULTI_PLANNER_UTILS_H */