diff --git a/README.md b/README.md
index 6670e72..ab2020f 100644
--- a/README.md
+++ b/README.md
@@ -133,13 +133,10 @@ function fetchUser(id) {
 }
 ```
 
-If you're setting up the store by hand, the default `thunk` export has an attached `thunk.withExtraArgument()` function that should be used to generate the correct thunk middleware:
+If you're setting up the store by hand, the named export `withExtraArgument()` function should be used to generate the correct thunk middleware:
 
 ```js
-const store = createStore(
-  reducer,
-  applyMiddleware(thunk.withExtraArgument(api))
-)
+const store = createStore(reducer, applyMiddleware(withExtraArgument(api)))
 ```
 
 ## Why Do I Need This?
diff --git a/src/index.ts b/src/index.ts
index d7f762e..58bab3d 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -36,15 +36,7 @@ function createThunkMiddleware<
   return middleware
 }
 
-export const thunk = createThunkMiddleware() as ThunkMiddleware & {
-  withExtraArgument<
-    ExtraThunkArg,
-    State = any,
-    BasicAction extends Action = AnyAction
-  >(
-    extraArgument: ExtraThunkArg
-  ): ThunkMiddleware<State, BasicAction, ExtraThunkArg>
-}
+export const thunk = createThunkMiddleware()
 
 // Export the factory function so users can create a customized version
 // with whatever "extra arg" they want to inject into their thunks
diff --git a/src/types.ts b/src/types.ts
index 091f760..973e4ac 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -78,7 +78,7 @@ export type ThunkActionDispatch<
  * @template State The redux state
  * @template BasicAction The (non-thunk) actions that can be dispatched
  * @template ExtraThunkArg An optional extra argument to pass to a thunk's
- * inner function. (Only used if you call `thunk.withExtraArgument()`)
+ * inner function. (Only used if you call `withExtraArgument()`)
  */
 export type ThunkMiddleware<
   State = any,
diff --git a/typescript_test/typescript.ts b/typescript_test/typescript.ts
index 9d37f87..2d22337 100644
--- a/typescript_test/typescript.ts
+++ b/typescript_test/typescript.ts
@@ -2,7 +2,7 @@
 import { applyMiddleware, bindActionCreators, createStore } from 'redux'
 import type { Action, AnyAction } from 'redux'
 
-import { thunk } from '../src/index'
+import { thunk, withExtraArgument } from '../src/index'
 import type {
   ThunkAction,
   ThunkActionDispatch,
@@ -70,7 +70,7 @@ store.dispatch(testGetState())
 const storeThunkArg = createStore(
   fakeReducer,
   applyMiddleware(
-    thunk.withExtraArgument('bar') as ThunkMiddleware<State, Actions, string>
+    withExtraArgument('bar') as ThunkMiddleware<State, Actions, string>
   )
 )
 storeThunkArg.dispatch({ type: 'FOO' })