diff --git a/packages/stream_chat_flutter/lib/src/message_input.dart b/packages/stream_chat_flutter/lib/src/message_input.dart
index 6ee5c435..61ac3ac6 100644
--- a/packages/stream_chat_flutter/lib/src/message_input.dart
+++ b/packages/stream_chat_flutter/lib/src/message_input.dart
@@ -84,6 +84,13 @@ typedef MessageRelatedBuilder = Widget Function(
   MessageInputController messageInputController,
 );
 
+/// Widget builder for a custom attachment picker.
+typedef AttachmentsPickerBuilder = Widget Function(
+  BuildContext context,
+  MessageInputController messageInputController,
+  StreamAttachmentPicker defaultPicker,
+);
+
 /// Location for actions on the [MessageInput]
 enum ActionsLocation {
   /// Align to left
@@ -330,7 +337,7 @@ class MessageInput extends StatefulWidget {
   final bool mentionAllAppUsers;
 
   /// Builds bottom sheet when attachment picker is opened.
-  final MessageRelatedBuilder? attachmentsPickerBuilder;
+  final AttachmentsPickerBuilder? attachmentsPickerBuilder;
 
   /// Builder for creating send button
   final MessageRelatedBuilder? sendButtonBuilder;
@@ -951,14 +958,7 @@ class MessageInputState extends State<MessageInput> {
   }
 
   Widget _buildFilePickerSection() {
-    if (_openFilePickerSection && widget.attachmentsPickerBuilder != null) {
-      return widget.attachmentsPickerBuilder!(
-        context,
-        messageInputController,
-      );
-    }
-
-    return StreamAttachmentPicker(
+    final picker = StreamAttachmentPicker(
       messageInputController: messageInputController,
       onFilePicked: pickFile,
       isOpen: _openFilePickerSection,
@@ -975,6 +975,16 @@ class MessageInputState extends State<MessageInput> {
       },
       onError: _showErrorAlert,
     );
+
+    if (_openFilePickerSection && widget.attachmentsPickerBuilder != null) {
+      return widget.attachmentsPickerBuilder!(
+        context,
+        messageInputController,
+        picker,
+      );
+    }
+
+    return picker;
   }
 
   Widget _buildMentionsOverlayEntry() {
diff --git a/packages/stream_chat_flutter/lib/src/mip/stream_attachment_picker.dart b/packages/stream_chat_flutter/lib/src/mip/stream_attachment_picker.dart
index ea7d54fb..f075a09c 100644
--- a/packages/stream_chat_flutter/lib/src/mip/stream_attachment_picker.dart
+++ b/packages/stream_chat_flutter/lib/src/mip/stream_attachment_picker.dart
@@ -9,16 +9,19 @@ import 'package:stream_chat_flutter/src/video_service.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 import 'package:video_compress/video_compress.dart';
 
+/// Callback for when a file has to be picked.
 typedef FilePickerCallback = void Function(
   DefaultAttachmentTypes fileType, {
   bool camera,
 });
 
+/// Callback for building an icon for a custom attachment type.
 typedef CustomAttachmentIconBuilder = Widget Function(
   BuildContext context,
   bool active,
 );
 
+///
 class StreamAttachmentPicker extends StatefulWidget {
   final bool isOpen;
   final double pickerSize;
@@ -65,6 +68,45 @@ class StreamAttachmentPicker extends StatefulWidget {
     this.customAttachmentTypes = const [],
   }) : super(key: key);
 
+  StreamAttachmentPicker copyWith({
+    Key? key,
+    MessageInputController? messageInputController,
+    FilePickerCallback? onFilePicked,
+    bool? isOpen,
+    double? pickerSize,
+    int? attachmentLimit,
+    AttachmentLimitExceedListener? onAttachmentLimitExceeded,
+    int? maxAttachmentSize,
+    VideoQuality? compressedVideoQuality,
+    int? compressedVideoFrameRate,
+    ValueChanged<bool>? onChangeInputState,
+    ValueChanged<String>? onError,
+    List<DefaultAttachmentTypes>? allowedAttachmentTypes,
+    List<CustomAttachmentType>? customAttachmentTypes = const [],
+  }) =>
+      StreamAttachmentPicker(
+        key: key ?? this.key,
+        messageInputController:
+            messageInputController ?? this.messageInputController,
+        onFilePicked: onFilePicked ?? this.onFilePicked,
+        isOpen: isOpen ?? this.isOpen,
+        pickerSize: pickerSize ?? this.pickerSize,
+        attachmentLimit: attachmentLimit ?? this.attachmentLimit,
+        onAttachmentLimitExceeded:
+            onAttachmentLimitExceeded ?? this.onAttachmentLimitExceeded,
+        maxAttachmentSize: maxAttachmentSize ?? this.maxAttachmentSize,
+        compressedVideoQuality:
+            compressedVideoQuality ?? this.compressedVideoQuality,
+        compressedVideoFrameRate:
+            compressedVideoFrameRate ?? this.compressedVideoFrameRate,
+        onChangeInputState: onChangeInputState ?? this.onChangeInputState,
+        onError: onError ?? this.onError,
+        allowedAttachmentTypes:
+            allowedAttachmentTypes ?? this.allowedAttachmentTypes,
+        customAttachmentTypes:
+            customAttachmentTypes ?? this.customAttachmentTypes,
+      );
+
   @override
   State<StreamAttachmentPicker> createState() => _StreamAttachmentPickerState();
 }