diff --git a/gpx/src/io.ts b/gpx/src/io.ts
index 65c074c2..a612c917 100644
--- a/gpx/src/io.ts
+++ b/gpx/src/io.ts
@@ -96,7 +96,9 @@ export function buildGPX(file: GPXFile, exclude: string[]): string {
         },
     });
 
-    gpx.attributes.creator = gpx.attributes.creator ?? 'https://gpx.studio';
+    if (!gpx.attributes)
+        gpx.attributes = {};
+    gpx.attributes['creator'] = gpx.attributes['creator'] ?? 'https://gpx.studio';
     gpx.attributes['version'] = '1.1';
     gpx.attributes['xmlns'] = 'http://www.topografix.com/GPX/1/1';
     gpx.attributes['xmlns:xsi'] = 'http://www.w3.org/2001/XMLSchema-instance';