diff --git a/index.js b/index.js
index d748bf37..72d0a32c 100644
--- a/index.js
+++ b/index.js
@@ -29,9 +29,9 @@ const run = async () => {
     const netlifyToken = process.env.NETLIFY_TOKEN;
     // In a PR, github.contex.sha refers to the last merge commit SHA
     // not the *latest commit* of the PR which is what Netlify uses. Instead,
-    // have to use github.context.event.pull_request.head.sha
+    // have to use github.context.payload.pull_request.head.sha
     // See: https://docs.github.com/en/developers/webhooks-and-events/webhook-events-and-payloads#pull_request
-    const commitSha = github.context.event.pull_request.head.sha;
+    const commitSha = github.context.payload.pull_request.head.sha;
     const MAX_TIMEOUT = Number(core.getInput("max_timeout")) || 60;
     const siteName = core.getInput("site_name");
     if (!netlifyToken) {