diff --git a/src/MessageBox/MessageBox.tsx b/src/MessageBox/MessageBox.tsx
index 87a7453..e06dc17 100644
--- a/src/MessageBox/MessageBox.tsx
+++ b/src/MessageBox/MessageBox.tsx
@@ -48,7 +48,7 @@ const MessageBox: React.FC<MessageBoxType> = ({ focus = false, notch = true, sty
 
   return (
     <div ref={messageRef} className={classNames('rce-container-mbox', props.className)} onClick={props.onClick}>
-      {props.renderAddCmp instanceof Function && props.renderAddCmp()}
+      {props.renderAddCmp instanceof Function ? props.renderAddCmp() : props.renderAddCmp}
       {props.type === 'system' ? (
         <SystemMessage {...props} focus={focus} notch={notch} />
       ) : (
diff --git a/src/type.d.ts b/src/type.d.ts
index 1520037..e4685dd 100644
--- a/src/type.d.ts
+++ b/src/type.d.ts
@@ -521,7 +521,7 @@ export interface ISpotifyMessageProps extends ISpotifyMessage {}
  */
 export interface IMessageBoxProps {
   onMessageFocused?: any
-  renderAddCmp?: JSX.Element
+  renderAddCmp?: JSX.Element | (() => JSX.Element)
   onClick?: React.MouseEventHandler
   onOpen?: React.MouseEventHandler
   onPhotoError?: React.MouseEventHandler