--- a/taskcluster/taskgraph/transforms/diffoscope.py
+++ b/taskcluster/taskgraph/transforms/diffoscope.py
@@ -8,17 +8,17 @@ defined in kind.yml
 
 from __future__ import absolute_import, print_function, unicode_literals
 
 from taskgraph.transforms.base import TransformSequence
 from taskgraph.util.schema import (
     Schema,
     validate_schema,
 )
-from taskgraph.util.taskcluster import get_artifact_url
+from taskgraph.util.taskcluster import get_artifact_path, get_artifact_url
 from voluptuous import (
     Any,
     Optional,
     Required,
 )
 
 transforms = TransformSequence()
 
@@ -102,17 +102,17 @@ def fill_template(config, tasks):
             elif 'win' in os_hint:
                 artifact = 'target.zip'
             else:
                 raise Exception(
                     'Cannot figure out the OS for {!r}'.format(value))
             if previous_artifact is not None and previous_artifact != artifact:
                 raise Exception(
                     'Cannot compare builds from different OSes')
-            url = get_artifact_url(task_id, 'public/build/{}'.format(artifact))
+            url = get_artifact_url(task_id, get_artifact_path(task, artifact))
             urls[k] = {'task-reference': url}
             previous_artifact = artifact
 
         taskdesc = {
             'label': 'diff-' + name,
             'description': name,
             'treeherder': {
                 'symbol': task['symbol'],