diff --git a/src/url.js b/src/url.js
index 63368af..af1b235 100644
--- a/src/url.js
+++ b/src/url.js
@@ -377,5 +377,9 @@ export default function url(publicId, options = {}, config = {}) {
     }
     resultUrl = `${resultUrl}${appender}_a=${sdkAnalyticsSignature}`;
   }
+  if (options.auth_token) {
+    let appender = resultUrl.indexOf('?') >= 0 ? '&' : '?';
+    resultUrl = `${resultUrl}${appender}__cld_token__=${options.auth_token}`;
+  }
   return resultUrl;
 };
diff --git a/test/spec/automatic/cloudinary-spec.js b/test/spec/automatic/cloudinary-spec.js
index df3ac32..49f64fd 100644
--- a/test/spec/automatic/cloudinary-spec.js
+++ b/test/spec/automatic/cloudinary-spec.js
@@ -481,6 +481,14 @@ describe('Cloudinary', function() {
       }, `${protocol}//res.cloudinary.com/test123/image/upload/e_assist_colorblind/${publicId}`, {});
     });
   });
+  describe("Auth token", function () {
+    it('should support auth_token', function () {
+      const authToken = 'ip=111.222.111.222~exp=1512982559~acl=%2fimage%2fauthenticated%2f%2a~hmac=b17360091889151e9c2e2a7c713a074fdd29dc4ef1cc2fb897a0764664f3c48d';
+      return test_cloudinary_url(publicId, {
+        auth_token: authToken
+      }, `${protocol}//res.cloudinary.com/test123/image/upload/${publicId}?__cld_token__=${authToken}`, {});
+    });
+  });
 });
 
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