diff --git a/Include/internal/pycore_global_objects.h b/Include/internal/pycore_global_objects.h
index d0461fa7e82e8b..30c7c4e3bbd067 100644
--- a/Include/internal/pycore_global_objects.h
+++ b/Include/internal/pycore_global_objects.h
@@ -27,8 +27,6 @@ extern "C" {
     _PyRuntime.cached_objects.NAME
 
 struct _Py_cached_objects {
-    PyObject *str_replace_inf;
-
     PyObject *interned_strings;
 };
 
@@ -67,11 +65,14 @@ struct _Py_static_objects {
     (interp)->cached_objects.NAME
 
 struct _Py_interp_cached_objects {
-    int _not_set;
+    /* AST */
+    PyObject *str_replace_inf;
+
     /* object.__reduce__ */
     PyObject *objreduce;
     PyObject *type_slots_pname;
     pytype_slotdef *type_slots_ptrs[MAX_EQUIV];
+
 };
 
 #define _Py_INTERP_STATIC_OBJECT(interp, NAME) \
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index db0e597b7a5aa4..b44e303ac2594b 100755
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -1484,9 +1484,7 @@ def generate_ast_fini(module_state, f):
     for s in module_state:
         f.write("    Py_CLEAR(state->" + s + ');\n')
     f.write(textwrap.dedent("""
-                if (_PyInterpreterState_Get() == _PyInterpreterState_Main()) {
-                    Py_CLEAR(_Py_CACHED_OBJECT(str_replace_inf));
-                }
+                Py_CLEAR(_Py_INTERP_CACHED_OBJECT(interp, str_replace_inf));
 
             #if !defined(NDEBUG)
                 state->initialized = -1;
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index d113c47b95392e..6c878474afb192 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -263,9 +263,7 @@ void _PyAST_Fini(PyInterpreterState *interp)
     Py_CLEAR(state->vararg);
     Py_CLEAR(state->withitem_type);
 
-    if (_PyInterpreterState_Get() == _PyInterpreterState_Main()) {
-        Py_CLEAR(_Py_CACHED_OBJECT(str_replace_inf));
-    }
+    Py_CLEAR(_Py_INTERP_CACHED_OBJECT(interp, str_replace_inf));
 
 #if !defined(NDEBUG)
     state->initialized = -1;
diff --git a/Python/ast_unparse.c b/Python/ast_unparse.c
index 79b2e2f15ba243..8aff045101cc72 100644
--- a/Python/ast_unparse.c
+++ b/Python/ast_unparse.c
@@ -1,5 +1,6 @@
 #include "Python.h"
 #include "pycore_ast.h"           // expr_ty
+#include "pycore_pystate.h"       // _PyInterpreterState_GET()
 #include "pycore_runtime.h"       // _Py_ID()
 #include <float.h>                // DBL_MAX_10_EXP
 #include <stdbool.h>
@@ -13,7 +14,10 @@ _Py_DECLARE_STR(open_br, "{");
 _Py_DECLARE_STR(dbl_open_br, "{{");
 _Py_DECLARE_STR(close_br, "}");
 _Py_DECLARE_STR(dbl_close_br, "}}");
-#define _str_replace_inf _Py_CACHED_OBJECT(str_replace_inf)
+
+/* We would statically initialize this if doing so were simple enough. */
+#define _str_replace_inf(interp) \
+    _Py_INTERP_CACHED_OBJECT(interp, str_replace_inf)
 
 /* Forward declarations for recursion via helper functions. */
 static PyObject *
@@ -78,10 +82,11 @@ append_repr(_PyUnicodeWriter *writer, PyObject *obj)
     if ((PyFloat_CheckExact(obj) && Py_IS_INFINITY(PyFloat_AS_DOUBLE(obj))) ||
        PyComplex_CheckExact(obj))
     {
+        PyInterpreterState *interp = _PyInterpreterState_GET();
         PyObject *new_repr = PyUnicode_Replace(
             repr,
             &_Py_ID(inf),
-            _str_replace_inf,
+            _str_replace_inf(interp),
             -1
         );
         Py_DECREF(repr);
@@ -916,9 +921,13 @@ append_ast_expr(_PyUnicodeWriter *writer, expr_ty e, int level)
 static int
 maybe_init_static_strings(void)
 {
-    if (!_str_replace_inf &&
-        !(_str_replace_inf = PyUnicode_FromFormat("1e%d", 1 + DBL_MAX_10_EXP))) {
-        return -1;
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    if (_str_replace_inf(interp) == NULL) {
+        PyObject *tmp = PyUnicode_FromFormat("1e%d", 1 + DBL_MAX_10_EXP);
+        if (tmp == NULL) {
+            return -1;
+        }
+        _str_replace_inf(interp) = tmp;
     }
     return 0;
 }