diff --git a/recipe_modules/roll_util/api.py b/recipe_modules/roll_util/api.py
index ac74465..3553d05 100644
--- a/recipe_modules/roll_util/api.py
+++ b/recipe_modules/roll_util/api.py
@@ -318,9 +318,11 @@
     def fake_author(self, author):
         # Update the author's email address so it can be used for attribution
         # without literally attributing it to the author's account in Gerrit.
+        # Make sure not to add it twice, and there's no need to do this for
+        # service accounts.
         email = author.email
         prefix = 'pigweed.infra.roller.'
-        if prefix not in email:
+        if prefix not in email and not email.endswith('gserviceaccount.com'):
             user, domain = author.email.split('@')
             email = '{}@{}{}'.format(user, prefix, domain)