diff --git a/action.yml b/action.yml
index 46431b7..d76990f 100644
--- a/action.yml
+++ b/action.yml
@@ -73,6 +73,14 @@ runs:
       run: |
         . "$GITHUB_ACTION_PATH/utils.sh"
 
+        # If we were triggered by a PR then this is easy
+        if [ "$GITHUB_EVENT_NAME" = "pull_request" ]; then
+                log "Triggered by a pull request with index: $GITHUB_HEAD_REF"
+                log "Expected PR URL: $GITHUB_SERVER_URL/$GITHUB_REPOSITORY/pulls/$GITHUB_HEAD_REF"
+                echo "pr-number=$GITHUB_HEAD_REF" >> "$GIHUB_OUTPUT"
+                exit 0
+        fi
+
         log 'Determine head_ref'
         # For push & tag events it'll bet GITHUB_REF_NAME, for pull_request events it'll be GITHUB_HEAD_REF
         head_ref=${GITHUB_REF_NAME:-$GITHUB_HEAD_REF}