diff --git a/website/docs/theme-classic.md b/website/docs/theme-classic.md
index 9d3cc36ccb..2f7f41340e 100644
--- a/website/docs/theme-classic.md
+++ b/website/docs/theme-classic.md
@@ -94,6 +94,22 @@ const Example = () => {
 };
 ```
 
+:::note
+
+The component calling `useThemeContext` must be a child of the `Layout` component.
+
+```jsx
+function ExamplePage() {
+  return (
+    <Layout>
+      <Example />
+    </Layout>
+  );
+}
+```
+
+:::
+
 ## Navbar
 
 ### Navbar title & logo