diff --git a/flytekit/core/promise.py b/flytekit/core/promise.py
index aa4e5f3150a..e8aa17c0be1 100644
--- a/flytekit/core/promise.py
+++ b/flytekit/core/promise.py
@@ -1053,7 +1053,7 @@ def create_and_link_node(
 
     for k in sorted(interface.inputs):
         var = typed_interface.inputs[k]
-        if k not in kwargs:
+        if k not in kwargs and k not in interface.inputs_with_defaults:
             is_optional = False
             if var.type.union_type:
                 for variant in var.type.union_type.variants:
@@ -1079,7 +1079,7 @@ def create_and_link_node(
                 raise _user_exceptions.FlyteAssertion(error_msg)
             else:
                 continue
-        v = kwargs[k]
+        v = kwargs.get(k) or interface.inputs_with_defaults.get(k)[1]
         # This check ensures that tuples are not passed into a function, as tuples are not supported by Flyte
         # Usually a Tuple will indicate that multiple outputs from a previous task were accidentally passed
         # into the function.
@@ -1102,7 +1102,7 @@ def create_and_link_node(
         except Exception as e:
             raise AssertionError(f"Failed to Bind variable {k} for function {entity.name}.") from e
 
-    extra_inputs = used_inputs ^ set(kwargs.keys())
+    extra_inputs = used_inputs ^ (set(kwargs.keys()) | set(interface.inputs_with_defaults))
     if len(extra_inputs) > 0:
         raise _user_exceptions.FlyteAssertion(
             "Too many inputs were specified for the interface.  Extra inputs were: {}".format(extra_inputs)