diff --git a/.github/workflows/external-ci-approved.yml b/.github/workflows/external-ci-approved.yml
index 9bd3b330816..62c4beb0c65 100644
--- a/.github/workflows/external-ci-approved.yml
+++ b/.github/workflows/external-ci-approved.yml
@@ -2,7 +2,7 @@
 name: Mirror PRs for External CI
 
 on:
-  pull_request:
+  pull_request_target:
     types: [labeled]
 
 jobs:
@@ -16,6 +16,8 @@ jobs:
       uses: actions/checkout@v3
       with:
         fetch-depth: 0
+        # TODO remove guesswork
+        ref: ${{ github.event.pull_request.head.sha || github.event.pull_request_target.head.sha }}
         token: ${{ secrets.AZTEC_BOT_GITHUB_TOKEN }}
 
     - name: Set up Git