diff --git a/src/file.ts b/src/file.ts
index 7f3f7a8bb..b609e8b3d 100644
--- a/src/file.ts
+++ b/src/file.ts
@@ -2586,6 +2586,7 @@ class File extends ServiceObject<File> {
 
       fields = {
         ...fields,
+        bucket: this.bucket.name,
         key: this.name,
         'x-goog-date': nowISO,
         'x-goog-credential': credential,
@@ -2600,6 +2601,8 @@ class File extends ServiceObject<File> {
         }
       });
 
+      delete fields.bucket;
+
       const expiration = dateFormat.format(
         expires,
         'YYYY-MM-DD[T]HH:mm:ss[Z]',
diff --git a/test/file.ts b/test/file.ts
index a7c4420f7..963d58673 100644
--- a/test/file.ts
+++ b/test/file.ts
@@ -2822,13 +2822,15 @@ describe('File', () => {
       fakeTimer.restore();
     });
 
+    const fieldsToConditions = (fields: object) =>
+      Object.entries(fields).map(([k, v]) => ({[k]: v}));
+
     it('should create a signed policy', done => {
       CONFIG.fields = {
         'x-goog-meta-foo': 'bar',
       };
 
-      const fields = {
-        ...CONFIG.fields,
+      const requiredFields = {
         key: file.name,
         'x-goog-date': '20200101T000000Z',
         'x-goog-credential': `${CLIENT_EMAIL}/20200101/auto/storage/goog4_request`,
@@ -2836,9 +2838,11 @@ describe('File', () => {
       };
 
       const policy = {
-        conditions: Object.entries(fields).map(([key, value]) => ({
-          [key]: value,
-        })),
+        conditions: [
+          ...fieldsToConditions(CONFIG.fields),
+          {bucket: BUCKET.name},
+          ...fieldsToConditions(requiredFields),
+        ],
         expiration: dateFormat.format(
           new Date(CONFIG.expires),
           'YYYY-MM-DD[T]HH:mm:ss[Z]',
@@ -2851,6 +2855,12 @@ describe('File', () => {
       const EXPECTED_SIGNATURE = Buffer.from(SIGNATURE, 'base64').toString(
         'hex'
       );
+      const EXPECTED_FIELDS = {
+        ...CONFIG.fields,
+        ...requiredFields,
+        'x-goog-signature': EXPECTED_SIGNATURE,
+        policy: EXPECTED_POLICY,
+      };
 
       // eslint-disable-next-line @typescript-eslint/no-explicit-any
       file.generateSignedPostPolicyV4(
@@ -2859,11 +2869,7 @@ describe('File', () => {
           assert.ifError(err);
           assert(res.url, `${STORAGE_POST_POLICY_BASE_URL}/${BUCKET.name}`);
 
-          assert.deepStrictEqual(res.fields, {
-            ...fields,
-            'x-goog-signature': EXPECTED_SIGNATURE,
-            policy: EXPECTED_POLICY,
-          });
+          assert.deepStrictEqual(res.fields, EXPECTED_FIELDS);
 
           const signStub = BUCKET.storage.authClient.sign;
           assert.deepStrictEqual(