diff --git a/aiogram/utils/keyboard.py b/aiogram/utils/keyboard.py
index 84258e6d..9fcab689 100644
--- a/aiogram/utils/keyboard.py
+++ b/aiogram/utils/keyboard.py
@@ -236,6 +236,12 @@ class KeyboardBuilder(Generic[ButtonType]):
         return self
 
     def button(self, **kwargs: Any) -> "KeyboardBuilder[ButtonType]":
+        """
+        Add button to markup
+
+        :param kwargs:
+        :return:
+        """
         if isinstance(callback_data := kwargs.get("callback_data", None), CallbackData):
             kwargs["callback_data"] = callback_data.pack()
         button = self._button_type(**kwargs)
@@ -246,6 +252,17 @@ class KeyboardBuilder(Generic[ButtonType]):
             return ReplyKeyboardMarkup(keyboard=self.export(), **kwargs)
         return InlineKeyboardMarkup(inline_keyboard=self.export())
 
+    def attach(self, builder: "KeyboardBuilder[ButtonType]") -> "KeyboardBuilder[ButtonType]":
+        if not isinstance(builder, KeyboardBuilder):
+            raise ValueError(f"Only KeyboardBuilder can be attached, not {type(builder).__name__}")
+        if builder._button_type is not self._button_type:
+            raise ValueError(
+                f"Only builders with same button type can be attached, "
+                f"not {self._button_type.__name__} and {builder._button_type.__name__}"
+            )
+        self._markup.extend(builder.export())
+        return self
+
 
 def repeat_last(items: Iterable[T]) -> Generator[T, None, None]:
     items_iter = iter(items)
@@ -303,6 +320,18 @@ class InlineKeyboardBuilder(KeyboardBuilder[InlineKeyboardButton]):
         """
         return InlineKeyboardBuilder(markup=self.export())
 
+    @classmethod
+    def from_markup(
+        cls: Type["InlineKeyboardBuilder"], markup: InlineKeyboardMarkup
+    ) -> "InlineKeyboardBuilder":
+        """
+        Create builder from existing markup
+
+        :param markup:
+        :return:
+        """
+        return cls(markup=markup.inline_keyboard)
+
 
 class ReplyKeyboardBuilder(KeyboardBuilder[KeyboardButton]):
     """
@@ -336,3 +365,13 @@ class ReplyKeyboardBuilder(KeyboardBuilder[KeyboardButton]):
         :return:
         """
         return ReplyKeyboardBuilder(markup=self.export())
+
+    @classmethod
+    def from_markup(cls, markup: ReplyKeyboardMarkup) -> "ReplyKeyboardBuilder":
+        """
+        Create builder from existing markup
+
+        :param markup:
+        :return:
+        """
+        return cls(markup=markup.keyboard)
diff --git a/docs/utils/keyboard.rst b/docs/utils/keyboard.rst
index 8988244e..35559fc0 100644
--- a/docs/utils/keyboard.rst
+++ b/docs/utils/keyboard.rst
@@ -14,6 +14,8 @@ Keyboard builder helps to dynamically generate markup.
 Usage example
 =============
 
+For example you want to generate inline keyboard with 10 buttons
+
 .. code-block:: python
 
     builder = InlineKeyboardBuilder()
@@ -21,22 +23,45 @@ Usage example
     for index in range(1, 11):
         builder.button(text=f"Set {index}", callback_data=f"set:{index}")
 
+
+then adjust this buttons to some grid, for example first line will have 3 buttons, the next lines will have 2 buttons
+
+.. code-block::
+
     builder.adjust(3, 2)
 
+also you can attach another builder to this one
+
+.. code-block:: python
+
+    another_builder = InlineKeyboardBuilder(...)...  # Another builder with some buttons
+    builder.attach(another_builder)
+
+or you can attach some already generated markup
+
+.. code-block:: python
+
+    markup = InlineKeyboardMarkup(inline_keyboard=[...])  # Some markup
+    builder.attach(InlineKeyboardBuilder.from_markup(markup))
+
+and finally you can export this markup to use it in your message
+
+.. code-block:: python
+
     await message.answer("Some text here", reply_markup=builder.as_markup())
 
+Reply keyboard builder has the same interface
+
+.. warning::
+
+    Note that you can't attach reply keyboard builder to inline keyboard builder and vice versa
 
-Base builder
-============
-.. autoclass:: aiogram.utils.keyboard.ReplyKeyboardBuilder
-    :members: __init__, buttons, copy, export, add, row, adjust, button, as_markup
-    :undoc-members: True
 
 Inline Keyboard
 ===============
 
 .. autoclass:: aiogram.utils.keyboard.InlineKeyboardBuilder
-    :noindex:
+    :members: __init__, buttons, copy, export, add, row, adjust, from_markup, attach
 
     .. method:: button(text: str, url: Optional[str] = None, login_url: Optional[LoginUrl] = None, callback_data: Optional[Union[str, CallbackData]] = None, switch_inline_query: Optional[str] = None, switch_inline_query_current_chat: Optional[str] = None, callback_game: Optional[CallbackGame] = None, pay: Optional[bool] = None, **kwargs: Any) -> aiogram.utils.keyboard.InlineKeyboardBuilder
         :noindex:
@@ -52,7 +77,7 @@ Reply Keyboard
 ==============
 
 .. autoclass:: aiogram.utils.keyboard.ReplyKeyboardBuilder
-    :noindex:
+    :members: __init__, buttons, copy, export, add, row, adjust, from_markup, attach
 
     .. method:: button(text: str, request_contact: Optional[bool] = None, request_location: Optional[bool] = None, request_poll: Optional[KeyboardButtonPollType] = None, **kwargs: Any) -> aiogram.utils.keyboard.ReplyKeyboardBuilder
         :noindex:
diff --git a/tests/test_api/test_types/test_chat_join_request.py b/tests/test_api/test_types/test_chat_join_request.py
index a36dd935..ec442cb1 100644
--- a/tests/test_api/test_types/test_chat_join_request.py
+++ b/tests/test_api/test_types/test_chat_join_request.py
@@ -24,11 +24,7 @@ from aiogram.methods import (
     SendVideoNote,
     SendVoice,
 )
-from aiogram.types import (
-    Chat,
-    ChatJoinRequest,
-    User,
-)
+from aiogram.types import Chat, ChatJoinRequest, User
 
 
 class TestChatJoinRequest: