diff --git a/packages/core/src/common/logging/logger.utils.spec.ts b/packages/core/src/common/logging/logger.utils.spec.ts
index 96c56f5912..1a353468d8 100644
--- a/packages/core/src/common/logging/logger.utils.spec.ts
+++ b/packages/core/src/common/logging/logger.utils.spec.ts
@@ -206,6 +206,19 @@ describe('formatMessage', () => {
 
         strictEqual(actual, expected);
       });
+
+      it('should return a text with a well-formatted message (unexpected undefined status code).', () => {
+        const message = 'HTTP request - GET /foo/bar';
+        const params = {
+          statusCode: undefined,
+          responseTime: null,
+        };
+
+        const actual = formatMessage('info', message, params, 'dev', now);
+        const expected = `\u001b[90m[${localeTimeNow}]\u001b[39m \u001b[36mINFO\u001b[39m GET /foo/bar undefined - null ms`
+
+        strictEqual(actual, expected);
+      });
     });
 
     context('given the message is a socket.io log and is prefixed by "Socket.io message received -"', () => {
diff --git a/packages/core/src/common/logging/logger.utils.ts b/packages/core/src/common/logging/logger.utils.ts
index 0f4dfed136..cb8c9a6055 100644
--- a/packages/core/src/common/logging/logger.utils.ts
+++ b/packages/core/src/common/logging/logger.utils.ts
@@ -63,7 +63,7 @@ function getColoredStatusCode(statusCode: number | null): string {
   if (statusCode >= 200) {
     return `\u001b[32m${statusCode}\u001b[39m`;
   }
-  return statusCode.toString();
+  return `${statusCode}`;
 }
 
 function getColoredStatus(status: 'ok'|'error'): string {