diff --git a/src/prefs.js b/src/prefs.js
index 587b83224..f65229ec7 100644
--- a/src/prefs.js
+++ b/src/prefs.js
@@ -53,7 +53,7 @@ var AboutWidget = new Lang.Class({
         });
         this.add(aboutName);
 
-        let aboutVersion = new Gtk.Label({ label: ext.metadata.version });
+        let aboutVersion = new Gtk.Label({ label: ext.metadata.version.toString() });
         this.add(aboutVersion);
 
         let aboutDescription = new Gtk.Label({