diff --git a/app/Ninja/Transformers/TaskTransformer.php b/app/Ninja/Transformers/TaskTransformer.php
index 0571185e4022..a5a4538e906f 100644
--- a/app/Ninja/Transformers/TaskTransformer.php
+++ b/app/Ninja/Transformers/TaskTransformer.php
@@ -38,13 +38,18 @@ class TaskTransformer extends EntityTransformer
 
     public function transform(Task $task)
     {
+        if($task->invoice)
+            $invoiceId = $task->invoice->public_id;
+        else
+            $invoiceId = null;
+        
         return array_merge($this->getDefaults($task), [
             'id' => (int) $task->public_id,
             'description' => $task->description,
             'duration' => $task->getDuration(),
             'updated_at' => (int) $this->getTimestamp($task->updated_at),
             'archived_at' => (int) $this->getTimestamp($task->deleted_at),
-            'invoice_id' => (int) $task->invoice->public_id,
+            'invoice_id' => $invoiceId,
             'client_id' => (int) $task->client->public_id,
             'is_deleted' => (bool) $task->is_deleted,
             'time_log' => $task->time_log,