diff --git a/aiogram/methods/base.py b/aiogram/methods/base.py
index b2d35bec..66d4dde6 100644
--- a/aiogram/methods/base.py
+++ b/aiogram/methods/base.py
@@ -12,11 +12,16 @@ from typing import (
     TypeVar,
 )
 
-from pydantic import BaseModel, ConfigDict
-from pydantic.functional_validators import model_validator
+from pydantic import (
+    BaseModel,
+    ConfigDict,
+    SerializerFunctionWrapHandler,
+    model_serializer,
+    model_validator,
+)
 
 from aiogram.client.context_controller import BotContextController
-
+from aiogram.client.default import Default, DefaultBotProperties
 from ..types import InputFile, ResponseParameters
 from ..types.base import UNSET_TYPE
 
@@ -65,6 +70,22 @@ class TelegramMethod(BotContextController, BaseModel, Generic[TelegramType], ABC
             return values
         return {k: v for k, v in values.items() if not isinstance(v, UNSET_TYPE)}
 
+    @model_serializer(mode="wrap", when_used="json")
+    def json_serialize(self, handler: SerializerFunctionWrapHandler) -> Dict[str, Any]:
+        """
+        Replacing `Default` placeholders with actual values from bot defaults.
+        Ensures JSON serialization backward compatibility by handling non-standard objects.
+        """
+        if not isinstance(self, TelegramMethod):
+            return handler(self)
+        properties = self.bot.default if self.bot else DefaultBotProperties()
+        default_fields = {
+            field: properties[value.name]
+            for field in self.model_fields.keys()
+            if isinstance(value := getattr(self, field), Default)
+        }
+        return handler(self.model_copy(update=default_fields))
+
     if TYPE_CHECKING:
         __returning__: ClassVar[type]
         __api_method__: ClassVar[str]
diff --git a/aiogram/types/base.py b/aiogram/types/base.py
index f97cf03a..aa13c80a 100644
--- a/aiogram/types/base.py
+++ b/aiogram/types/base.py
@@ -1,10 +1,16 @@
 from typing import Any, Dict
 from unittest.mock import sentinel
 
-from pydantic import BaseModel, ConfigDict, model_validator
+from pydantic import (
+    BaseModel,
+    ConfigDict,
+    SerializerFunctionWrapHandler,
+    model_serializer,
+    model_validator,
+)
 
 from aiogram.client.context_controller import BotContextController
-from aiogram.client.default import Default
+from aiogram.client.default import Default, DefaultBotProperties
 
 
 class TelegramObject(BotContextController, BaseModel):
@@ -36,6 +42,22 @@ class TelegramObject(BotContextController, BaseModel):
             return values
         return {k: v for k, v in values.items() if not isinstance(v, UNSET_TYPE)}
 
+    @model_serializer(mode="wrap", when_used="json")
+    def json_serialize(self, handler: SerializerFunctionWrapHandler) -> Dict[str, Any]:
+        """
+        Replacing `Default` placeholders with actual values from bot defaults.
+        Ensures JSON serialization backward compatibility by handling non-standard objects.
+        """
+        if not isinstance(self, TelegramObject):
+            return handler(self)
+        properties = self.bot.default if self.bot else DefaultBotProperties()
+        default_fields = {
+            field: properties[value.name]
+            for field in self.model_fields.keys()
+            if isinstance(value := getattr(self, field), Default)
+        }
+        return handler(self.model_copy(update=default_fields))
+
 
 class MutableTelegramObject(TelegramObject):
     model_config = ConfigDict(
diff --git a/tests/test_api/test_methods/test_base.py b/tests/test_api/test_methods/test_base.py
index 085650f3..66cfd101 100644
--- a/tests/test_api/test_methods/test_base.py
+++ b/tests/test_api/test_methods/test_base.py
@@ -1,9 +1,11 @@
+from typing import Any, Dict
 from unittest.mock import sentinel
 
 import pytest
 
-from aiogram.methods import GetMe, TelegramMethod
-from aiogram.types import TelegramObject, User
+from aiogram.client.default import Default
+from aiogram.methods import GetMe, SendMessage, TelegramMethod
+from aiogram.types import LinkPreviewOptions, TelegramObject, User
 from tests.mocked_bot import MockedBot
 
 
@@ -26,6 +28,25 @@ class TestTelegramMethodRemoveUnset:
         assert obj.remove_unset("") == ""
 
 
+class TestTelegramMethodJsonSerialize:
+    @pytest.mark.parametrize(
+        "obj",
+        [
+            SendMessage(
+                chat_id=1,
+                text="test",
+            ),
+            LinkPreviewOptions(),
+        ],
+    )
+    def test_json_serialize(self, obj):
+        def has_defaults(dump: Dict[str, Any]) -> bool:
+            return any(isinstance(value, Default) for value in dump.values())
+
+        assert has_defaults(obj.model_dump())
+        assert not has_defaults(obj.model_dump(mode="json"))
+
+
 class TestTelegramMethodCall:
     async def test_async_emit_unsuccessful(self, bot: MockedBot):
         with pytest.raises(