diff --git a/lib/datasource/rubygems/get.ts b/lib/datasource/rubygems/get.ts
index 2aabd2877a16b8..5e44a7cb838af0 100644
--- a/lib/datasource/rubygems/get.ts
+++ b/lib/datasource/rubygems/get.ts
@@ -23,7 +23,7 @@ export async function fetch(
 
   const url = urlJoin(registry, path, `${dependency}.json`);
 
-  logger.trace({ dependency }, `RubyGems lookup request: ${url}`);
+  logger.trace({ dependency }, `RubyGems lookup request: ${String(url)}`);
   const response = (await http.getJson(url, { headers })) || {
     body: undefined,
   };