diff --git a/lib/dl_pydantic/dl_pydantic/typed.py b/lib/dl_pydantic/dl_pydantic/typed.py
index 06e41fa00..00f8a659d 100644
--- a/lib/dl_pydantic/dl_pydantic/typed.py
+++ b/lib/dl_pydantic/dl_pydantic/typed.py
@@ -25,6 +25,7 @@
 class TypedMeta(pydantic_model_construction.ModelMetaclass):
     def __init__(cls, name: str, bases: tuple[type, ...], attrs: dict[str, Any]):
         cls._classes: dict[str, type["TypedBaseModel"]] = {}
+        cls._unknown_class: type["TypedBaseModel"] | None = None
 
 
 class TypedBaseModel(base.BaseModel, metaclass=TypedMeta):
@@ -37,13 +38,24 @@ class TypedBaseModel(base.BaseModel, metaclass=TypedMeta):
     @classmethod
     def register(cls, name: str, class_: Type) -> None:  # noqa: UP006
         if name in cls._classes:
-            raise ValueError(f"Class with name '{name}' already registered")
+            raise ValueError(f"{cls.__name__}(type={name}) already registered")
 
         if not issubclass(class_, cls):
             raise ValueError(f"Class '{class_}' must be subclass of '{cls}'")
 
         cls._classes[name] = class_
-        LOGGER.info(f"Registered class '{name}' as '{class_}'")
+        LOGGER.debug("Registered %s(type=%s): %s", cls.__name__, name, class_)
+
+    @classmethod
+    def register_unknown(cls, class_: Type) -> None:  # noqa: UP006
+        if cls._unknown_class is not None:
+            raise ValueError("Unknown class already registered")
+
+        if not issubclass(class_, cls):
+            raise ValueError(f"Class '{class_}' must be subclass of {cls}")
+
+        cls._unknown_class = class_
+        LOGGER.debug("Registered unknown for %s: %s", cls.__name__, class_)
 
     @classmethod
     def _prepare_data(cls, data: dict[str, Any]) -> dict[str, Any]:
@@ -66,9 +78,12 @@ def factory(cls, data: Any) -> Self:
             raise ValueError("Data must be dict")
 
         class_name = cls._get_class_name(data)
-        if class_name not in cls._classes:
+        if class_name in cls._classes:
+            class_ = cls._classes[class_name]
+        elif cls._unknown_class is not None:
+            class_ = cls._unknown_class
+        else:
             raise ValueError(f"Unknown type: {class_name}")
-        class_ = cls._classes[class_name]
 
         data = class_._prepare_data(data)
 
diff --git a/lib/dl_pydantic/dl_pydantic_tests/unit/test_typed.py b/lib/dl_pydantic/dl_pydantic_tests/unit/test_typed.py
index 07b107085..8f783f9c4 100644
--- a/lib/dl_pydantic/dl_pydantic_tests/unit/test_typed.py
+++ b/lib/dl_pydantic/dl_pydantic_tests/unit/test_typed.py
@@ -378,3 +378,39 @@ class Root(dl_pydantic.BaseModel):
     root = Root.model_validate({"children": {"child": {}}})
 
     assert isinstance(root.children["child"], Child)
+
+
+def test_register_unknown() -> None:
+    class Base(dl_pydantic.TypedBaseModel):
+        ...
+
+    class Child(Base):
+        ...
+
+    Base.register("child", Child)
+
+    with pytest.raises(ValueError):
+        Base.factory({"type": "bebebe"})
+
+    class UnknownChild(Base):
+        type: str = "unknown"
+        raw_data: typing.Any
+
+        @pydantic.model_validator(mode="before")
+        @classmethod
+        def transform_to_raw_data(cls, data: typing.Any) -> typing.Any:
+            return {"raw_data": data}
+
+    Base.register_unknown(UnknownChild)
+
+    raw_data = {"type": "bebebe"}
+    data = Base.factory(raw_data)
+
+    assert isinstance(data, UnknownChild)
+    assert data.type == "unknown"
+    assert data.raw_data == raw_data
+
+    raw_data = {"type": "child"}
+    data = Base.factory(raw_data)
+
+    assert isinstance(data, Child)