diff --git a/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php b/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
index 07ba3b0bdfce..64e84e2e403a 100644
--- a/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
+++ b/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
@@ -1070,6 +1070,8 @@ protected function setAttributeMarkedMutatedAttributeValue($key, $value)
         } else {
             unset($this->attributeCastCache[$key]);
         }
+
+        return $this;
     }
 
     /**
diff --git a/tests/Integration/Database/DatabaseEloquentModelAttributeCastingTest.php b/tests/Integration/Database/DatabaseEloquentModelAttributeCastingTest.php
index e3e8da8f4c99..a6263a096e91 100644
--- a/tests/Integration/Database/DatabaseEloquentModelAttributeCastingTest.php
+++ b/tests/Integration/Database/DatabaseEloquentModelAttributeCastingTest.php
@@ -47,6 +47,10 @@ public function testBasicCustomCasting()
 
         $this->assertSame('DRIES', $model->uppercase);
 
+        $model = $model->setAttribute('uppercase', 'james');
+
+        $this->assertInstanceOf(TestEloquentModelWithAttributeCast::class, $model);
+
         $model = new TestEloquentModelWithAttributeCast;
 
         $model->address = $address = new AttributeCastAddress('110 Kingsbrook St.', 'My Childhood House');