diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 1ed4a3900..db863080d 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -32,7 +32,7 @@ jobs:
             fi
           elif ${{ github.event_name == 'pull_request_target' }}; then
             echo "branch=pull/${{ github.event.number }}/merge" >> "$GITHUB_OUTPUT"
-            if ${{ github.event.head.repo.html_url != github.repository.html_url }}; then
+            if ${{ github.event.pull_request.head.repo.html_url != github.repository.html_url }}; then
               echo "environment=External PR" >> "$GITHUB_OUTPUT"
             else
               echo "environment=Preview" >> "$GITHUB_OUTPUT"