diff --git a/Lib/argparse.py b/Lib/argparse.py
index 100ef9f55cd2f7..e9d2ea34c0b122 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -2234,6 +2234,18 @@ def _match_arguments_partial(self, actions, arg_strings_pattern):
         # return the list of arg string counts
         return result
 
+    def _extract_optional_arguments(self):
+        optionals = []
+
+        for action in self._actions:
+            if not isinstance(action, _SubParsersAction):
+                continue
+            if hasattr(action, 'choices'):
+                for choices in action.choices.values():
+                    for action in choices._actions:
+                        optionals.extend(action.option_strings)
+        return optionals
+
     def _parse_optional(self, arg_string):
         # if it's an empty string, it was meant to be a positional
         if not arg_string:
@@ -2262,6 +2274,12 @@ def _parse_optional(self, arg_string):
         # and all actions in the parser for possible interpretations
         option_tuples = self._get_option_tuples(arg_string)
 
+        # if the parameter string exists,
+        # similar matching exception isn't thrown
+        optionals = self._extract_optional_arguments()
+        if arg_string in optionals:
+            return None
+
         # if multiple actions match, the option string was ambiguous
         if len(option_tuples) > 1:
             options = ', '.join([option_string
diff --git a/Misc/NEWS.d/next/Library/2024-09-12-09-52-15.gh-issue-109990.belDmD.rst b/Misc/NEWS.d/next/Library/2024-09-12-09-52-15.gh-issue-109990.belDmD.rst
new file mode 100644
index 00000000000000..71ab661b238c0f
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-09-12-09-52-15.gh-issue-109990.belDmD.rst
@@ -0,0 +1,2 @@
+Enhance handling of optional arguments in the :meth:`argparse.ArgumentParser.add_argument`
+of the :class:`argparse.ArgumentParser` in the :mod:`argparse`.