diff --git a/packages/types/src/extrinsic/signedExtensions/index.ts b/packages/types/src/extrinsic/signedExtensions/index.ts
index fab342e2ba..eb824bf44d 100644
--- a/packages/types/src/extrinsic/signedExtensions/index.ts
+++ b/packages/types/src/extrinsic/signedExtensions/index.ts
@@ -5,16 +5,19 @@ import type { ExtDef, ExtInfo, ExtTypes } from './types';
 
 import { polkadot } from './polkadot';
 import { shell } from './shell';
+import { statemint } from './statemint';
 import { substrate } from './substrate';
 
 // A mapping of the known signed extensions to the extra fields that they contain. Unlike in the actual extensions,
 // we define the extra fields not as a Tuple, but rather as a struct so they can be named. These will be expanded
 // into the various fields when added to the payload (we only support V4 onwards with these, V3 and earlier are
 // deemed fixed and non-changeable)
+// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
 const allExtensions: ExtDef = {
   ...substrate,
   ...shell,
-  ...polkadot
+  ...polkadot,
+  ...statemint
 };
 
 // the v4 signed extensions (the order is important here, as applied by default)
diff --git a/packages/types/src/extrinsic/signedExtensions/statemint.ts b/packages/types/src/extrinsic/signedExtensions/statemint.ts
new file mode 100644
index 0000000000..fc9c37d16a
--- /dev/null
+++ b/packages/types/src/extrinsic/signedExtensions/statemint.ts
@@ -0,0 +1,15 @@
+// Copyright 2017-2021 @polkadot/types authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { ExtDef } from './types';
+
+export const statemint: ExtDef = {
+  ChargeAssetTxPayment: {
+    extrinsic: {
+      tip: 'Compact<Balance>',
+      // eslint-disable-next-line sort-keys
+      assetId: 'Option<AssetId>'
+    },
+    payload: {}
+  }
+};