diff --git a/dist/index.js b/dist/index.js
index c39596b..1665cb0 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -2110,7 +2110,8 @@ function testRef(git, ref, commit) {
         // refs/tags/
         else if (upperRef.startsWith('REFS/TAGS/')) {
             const tagName = ref.substring('refs/tags/'.length);
-            return ((yield git.tagExists(tagName)) && commit === (yield git.revParse(ref)));
+            return ((yield git.tagExists(tagName)) &&
+                commit === (yield git.revParse(`${ref}^{commit}`)));
         }
         // Unexpected
         else {
diff --git a/src/ref-helper.ts b/src/ref-helper.ts
index 047e906..ee0724a 100644
--- a/src/ref-helper.ts
+++ b/src/ref-helper.ts
@@ -167,7 +167,8 @@ export async function testRef(
   else if (upperRef.startsWith('REFS/TAGS/')) {
     const tagName = ref.substring('refs/tags/'.length)
     return (
-      (await git.tagExists(tagName)) && commit === (await git.revParse(ref))
+      (await git.tagExists(tagName)) &&
+      commit === (await git.revParse(`${ref}^{commit}`))
     )
   }
   // Unexpected