diff --git a/src/Picqer/Financials/Exact/PurchaseOrder.php b/src/Picqer/Financials/Exact/PurchaseOrder.php
index 7ca7cb10..e50c68ad 100644
--- a/src/Picqer/Financials/Exact/PurchaseOrder.php
+++ b/src/Picqer/Financials/Exact/PurchaseOrder.php
@@ -159,4 +159,13 @@ public function addItem(array $array)
         }
         $this->attributes['PurchaseOrderLines'][] = $array;
     }
+
+    public function getPurchaseOrderLines($select = '')
+    {
+        if (array_key_exists('__deferred', $this->attributes['PurchaseOrderLines'])) {
+            $this->attributes['PurchaseOrderLines'] = (new PurchaseOrderLine($this->connection()))->filter("PurchaseOrderID eq guid'{$this->PurchaseOrderID}'", '', $select);
+        }
+
+        return $this->attributes['PurchaseOrderLines'];
+    }
 }