diff --git a/CHANGELOG.md b/CHANGELOG.md
index 68352f9..815fde2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
+## [1.5.3]
+
+### Fixed
+
+- `FnWithKwargs` call function fixed
+
 ## [1.5.2]
 
 ### Added
diff --git a/kaizo/utils/fn.py b/kaizo/utils/fn.py
index cb3dbf9..6f13ab0 100644
--- a/kaizo/utils/fn.py
+++ b/kaizo/utils/fn.py
@@ -1,5 +1,5 @@
 from collections.abc import Callable
-from copy import copy
+from functools import partial
 from typing import Generic, TypeVar
 
 R = TypeVar("R")
@@ -7,8 +7,8 @@
 
 class FnWithKwargs(Generic[R]):
     fn: Callable[..., R]
-    args: tuple | None
-    kwargs: dict[str] | None
+    args: tuple
+    kwargs: dict[str]
 
     def __init__(
         self,
@@ -16,22 +16,20 @@ def __init__(
         args: tuple | None = None,
         kwargs: dict[str] | None = None,
     ) -> None:
-        self.fn = fn
+        if args is None:
+            args = ()
 
         if kwargs is None:
             kwargs = {}
 
+        self.fn = fn
         self.args = args
         self.kwargs = kwargs
 
     def __call__(self, *args, **kwargs) -> R:
-        call_kwargs = copy(self.kwargs)
-        call_kwargs.update(kwargs)
-
-        if self.args is not None:
-            args = self.args
+        fn = partial(self.fn, *self.args, **self.kwargs)
 
-        return self.fn(*args, **call_kwargs)
+        return fn(*args, **kwargs)
 
     def update(self, **kwargs) -> None:
         self.kwargs.update(kwargs)
diff --git a/pyproject.toml b/pyproject.toml
index 2105df5..9c8f5c1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "kaizo"
-version = "1.5.2"
+version = "1.5.3"
 description = "declarative YAML-based configuration parser"
 authors = [{ name = "Mohammad Ghazanfari", email = "mgh.5225@gmail.com" }]
 readme = "README.md"
diff --git a/tests/test_lazy_injection.py b/tests/test_lazy_injection.py
new file mode 100644
index 0000000..e79839a
--- /dev/null
+++ b/tests/test_lazy_injection.py
@@ -0,0 +1,46 @@
+from pathlib import Path
+
+from kaizo import ConfigParser
+from kaizo.utils import FnWithKwargs
+
+X = 5
+Y = 6
+Z = 7
+
+main_py = f"""
+def fn(x,y,z):
+  return (x,y,z)
+
+def fn2(cb):
+    return cb({X},{Y})
+"""
+
+
+lazy_config = f"""
+local: main.py
+a:
+    module: local
+    source: fn
+    lazy: true
+    args:
+        z: {Z}
+b:
+    module: local
+    source: fn2
+    args:
+        cb: .{{a}}
+"""
+
+
+def test_lazy_injection(tmp_path: Path) -> None:
+    module = tmp_path / "main.py"
+    module.write_text(main_py)
+
+    cfg_file = tmp_path / "cfg.yml"
+    cfg_file.write_text(lazy_config)
+
+    parser = ConfigParser(cfg_file, kwargs={"injected": X})
+    out = parser.parse()
+
+    assert isinstance(out["a"], FnWithKwargs)
+    assert out["b"] == (X, Y, Z)