diff --git a/src/Avatar.php b/src/Avatar.php
index aa60b45..536271e 100644
--- a/src/Avatar.php
+++ b/src/Avatar.php
@@ -186,7 +186,7 @@ public function toBase64()
 
         $this->buildAvatar();
 
-        $base64 = $this->image->encode('data-url');
+        $base64 = (string)$this->image->encode('data-url');
 
         $this->cache->forever($key, $base64);