diff --git a/app/Http/Controllers/ProjectController.php b/app/Http/Controllers/ProjectController.php
index 6277825cae..25a069e96c 100644
--- a/app/Http/Controllers/ProjectController.php
+++ b/app/Http/Controllers/ProjectController.php
@@ -607,7 +607,7 @@ class ProjectController extends BaseController
         $this->entity_transformer = InvoiceTransformer::class;
         $this->entity_type = Invoice::class;
 
-        $invoice = $this->project_repo->invoice($project);
+        $invoice = $this->project_repo->invoice(collect([$project]));
 
         return $this->itemResponse($invoice);
     }
diff --git a/app/Repositories/ProjectRepository.php b/app/Repositories/ProjectRepository.php
index b11c65b5b5..fdc6fb459d 100644
--- a/app/Repositories/ProjectRepository.php
+++ b/app/Repositories/ProjectRepository.php
@@ -21,13 +21,23 @@ use App\Models\Project;
  * Class for project repository.
  */
 class ProjectRepository extends BaseRepository
-{
+{    
+    /**
+     * Invoices a collection of projects into a single invoice.
+     *
+     * @param  mixed $projects
+     * @return App\Models\Invoice
+     */
     public function invoice(mixed $projects)
     {
         $_project = $projects->first();
 
         $invoice = InvoiceFactory::create($_project->company_id, $_project->user_id);
         $invoice->client_id = $_project->client_id;
+
+        if(count($projects) == 1) {
+            $invoice->project_id = $_project->id;
+        }
         // $invoice->project_id = $project->id;
 
         $lines = [];