diff --git a/api/arkui/component/extendableComponent.static.d.ets b/api/arkui/component/extendableComponent.static.d.ets
index a0d820a7ce6882ce82b20947958272eddfb86b9e..84d4c9e52f99a75a0c48bb87a8aac03d93c065d3 100644
--- a/api/arkui/component/extendableComponent.static.d.ets
+++ b/api/arkui/component/extendableComponent.static.d.ets
@@ -19,8 +19,9 @@
  * @arkts 1.2
  */
 
-import { UIContext } from '@ohos.arkui.UIContext'
-import { Builder } from './builder'
+import { Builder } from './builder';
+import { Theme } from '@ohos.arkui.theme';
+import { UIContext } from '@ohos.arkui.UIContext';
 import { Optional, NavDestinationInfo, NavigationInfo, RouterPageInfo } from './common';
 
 /**
@@ -80,6 +81,15 @@ export declare interface LifeCycle {
  * @since 20
  */
 export declare abstract class ExtendableComponent implements LifeCycle {
+    /**
+     * onWillApplyTheme function is a custom hook to get active theme object from the context.
+     *
+     * @param { Theme } theme - Custom theme init params.
+     * @syscap SystemCapability.ArkUI.ArkUI.Full
+     * @since 20
+     */
+    onWillApplyTheme(theme: Theme): void;
+
     /**
      * Get current UIContext.
      *