diff --git a/colour/continuous/signal.py b/colour/continuous/signal.py
index 9a5cb5e692..229e4014f3 100644
--- a/colour/continuous/signal.py
+++ b/colour/continuous/signal.py
@@ -276,7 +276,7 @@ def __init__(
             "extrapolator_kwargs", self._extrapolator_kwargs
         )
 
-        self._create_function()
+        self._function: Callable | None = None
 
     @property
     def dtype(self) -> Type[DTypeFloating]:
@@ -349,7 +349,7 @@ def domain(self, value: ArrayLike):
             self._range = np.resize(self._range, value.shape)
 
         self._domain = value
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     @property
     def range(self) -> NDArray:
@@ -389,7 +389,7 @@ def range(self, value: ArrayLike):
         )
 
         self._range = value
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     @property
     def interpolator(self) -> Type[TypeInterpolator]:
@@ -416,7 +416,7 @@ def interpolator(self, value: Type[TypeInterpolator]):
 
         # TODO: Check for interpolator compatibility.
         self._interpolator = value
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     @property
     def interpolator_kwargs(self) -> Dict:
@@ -449,7 +449,7 @@ def interpolator_kwargs(self, value: dict):
         )
 
         self._interpolator_kwargs = value
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     @property
     def extrapolator(self) -> Type[TypeExtrapolator]:
@@ -476,7 +476,7 @@ def extrapolator(self, value: Type[TypeExtrapolator]):
 
         # TODO: Check for extrapolator compatibility.
         self._extrapolator = value
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     @property
     def extrapolator_kwargs(self) -> Dict:
@@ -509,7 +509,7 @@ def extrapolator_kwargs(self, value: dict):
         )
 
         self._extrapolator_kwargs = value
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     @property
     def function(self) -> Callable:
@@ -522,7 +522,43 @@ def function(self) -> Callable:
             Continuous signal callable.
         """
 
-        return self._function
+        if self._function is None:
+            # Create the underlying continuous function
+
+            if self._domain.size != 0 and self._range.size != 0:
+                self._function = self._extrapolator(
+                    self._interpolator(
+                        self.domain, self.range, **self._interpolator_kwargs
+                    ),
+                    **self._extrapolator_kwargs,
+                )
+            else:
+
+                def _undefined_function(*args: Any, **kwargs: Any):
+                    """
+                    Raise a :class:`ValueError` exception.
+
+                    Other Parameters
+                    ----------------
+                    args
+                        Arguments.
+                    kwargs
+                        Keywords arguments.
+
+                    Raises
+                    ------
+                    ValueError
+                    """
+
+                    raise ValueError(
+                        "Underlying signal interpolator function does not exists, "
+                        "please ensure you defined both "
+                        '"domain" and "range" variables!'
+                    )
+
+                self._function = cast(Callable, _undefined_function)
+
+        return cast(Callable, self._function)
 
     def __str__(self) -> str:
         """
@@ -677,7 +713,7 @@ def __getitem__(
         if isinstance(x, slice):
             return self._range[x]
         else:
-            return self._function(x)
+            return self.function(x)
 
     def __setitem__(
         self, x: Union[FloatingOrArrayLike, slice], y: FloatingOrArrayLike
@@ -769,7 +805,7 @@ def __setitem__(
                 self._domain = np.insert(self._domain, indexes, x_nm)
                 self._range = np.insert(self._range, indexes, y[~mask])
 
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     def __contains__(self, x: Union[FloatingOrArrayLike, slice]) -> bool:
         """
@@ -893,42 +929,6 @@ def __ne__(self, other: Any) -> bool:
 
         return not (self == other)
 
-    def _create_function(self):
-        """Create the continuous signal underlying function."""
-
-        if self._domain.size != 0 and self._range.size != 0:
-            self._function = self._extrapolator(
-                self._interpolator(
-                    self.domain, self.range, **self._interpolator_kwargs
-                ),
-                **self._extrapolator_kwargs,
-            )
-        else:
-
-            def _undefined_function(*args: Any, **kwargs: Any):
-                """
-                Raise a :class:`ValueError` exception.
-
-                Other Parameters
-                ----------------
-                args
-                    Arguments.
-                kwargs
-                    Keywords arguments.
-
-                Raises
-                ------
-                ValueError
-                """
-
-                raise ValueError(
-                    "Underlying signal interpolator function does not exists, "
-                    "please ensure you defined both "
-                    '"domain" and "range" variables!'
-                )
-
-            self._function = _undefined_function
-
     def _fill_domain_nan(
         self,
         method: Union[
@@ -955,7 +955,7 @@ def _fill_domain_nan(
         """
 
         self._domain = fill_nan(self._domain, method, default)
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     def _fill_range_nan(
         self,
@@ -983,7 +983,7 @@ def _fill_range_nan(
         """
 
         self._range = fill_nan(self._range, method, default)
-        self._create_function()
+        self._function = None  # Invalidate internal _function
 
     def arithmetical_operation(
         self,