diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index b8f9bf087467..8433a9cee6df 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -4622,8 +4622,8 @@ def union_tuple_fallback_item(self, left_type: TupleType) -> Type:
     def visit_typeddict_index_expr(
         self, td_type: TypedDictType, index: Expression, setitem: bool = False
     ) -> tuple[Type, set[str]]:
-        if isinstance(index, StrExpr):
-            key_names = [index.value]
+        if isinstance(folded_index := constant_fold_expr(index, "unused"), str):
+            key_names = [folded_index]
         else:
             typ = get_proper_type(self.accept(index))
             if isinstance(typ, UnionType):