diff --git a/src/Illuminate/Database/Eloquent/Builder.php b/src/Illuminate/Database/Eloquent/Builder.php
index 306c42761618..b31cda531a64 100755
--- a/src/Illuminate/Database/Eloquent/Builder.php
+++ b/src/Illuminate/Database/Eloquent/Builder.php
@@ -559,9 +559,15 @@ protected function addUpdatedAtColumn(array $values)
             return $values;
         }
 
-        $column = $this->model->getUpdatedAtColumn();
+        if (count($this->getQuery()->joins) > 0) {
+            $column = $this->model->getQualifiedUpdatedAtColumn();
+        } else {
+            $column = $this->model->getUpdatedAtColumn();
+        }
 
-        return Arr::add($values, $column, $this->model->freshTimestampString());
+        return array_merge($values, [
+            $column => $this->model->freshTimestampString(),
+        ]);
     }
 
     /**
diff --git a/src/Illuminate/Database/Eloquent/Model.php b/src/Illuminate/Database/Eloquent/Model.php
index 55bb2916fa70..69b82bac7fe2 100755
--- a/src/Illuminate/Database/Eloquent/Model.php
+++ b/src/Illuminate/Database/Eloquent/Model.php
@@ -1786,6 +1786,16 @@ public function getUpdatedAtColumn()
         return static::UPDATED_AT;
     }
 
+    /**
+     * Get the fully qualified "updated at" column.
+     *
+     * @return string
+     */
+    public function getQualifiedUpdatedAtColumn()
+    {
+        return $this->getTable().'.'.$this->getUpdatedAtColumn();
+    }
+
     /**
      * Get a fresh timestamp for the model.
      *