diff --git a/Misc/NEWS.d/next/C API/2020-06-01-16-12-37.bpo-40826.zQzFoK.rst b/Misc/NEWS.d/next/C API/2020-06-01-16-12-37.bpo-40826.zQzFoK.rst
new file mode 100644
index 00000000000..0d7a36c3eb4
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2020-06-01-16-12-37.bpo-40826.zQzFoK.rst	
@@ -0,0 +1,2 @@
+:c:func:`PyOS_InterruptOccurred` now fails with a fatal error if it is
+called with the GIL released.
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index 8348971c353..6d340a68634 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -1782,8 +1782,9 @@ PyOS_FiniInterrupts(void)
 int
 PyOS_InterruptOccurred(void)
 {
-    PyInterpreterState *interp = _PyInterpreterState_GET();
-    if (!_Py_ThreadCanHandleSignals(interp)) {
+    PyThreadState *tstate = _PyThreadState_GET();
+    _Py_EnsureTstateNotNULL(tstate);
+    if (!_Py_ThreadCanHandleSignals(tstate->interp)) {
         return 0;
     }