diff --git a/tools/pybind11NewTools.cmake b/tools/pybind11NewTools.cmake
index 087784c22c..f228a8c278 100644
--- a/tools/pybind11NewTools.cmake
+++ b/tools/pybind11NewTools.cmake
@@ -125,14 +125,22 @@ if(NOT _PYBIND11_CROSSCOMPILING)
     unset(PYTHON_MODULE_EXTENSION CACHE)
   endif()
 
-  set(PYBIND11_PYTHON_EXECUTABLE_LAST
-      "${${_Python}_EXECUTABLE}"
-      CACHE INTERNAL "Python executable during the last CMake run")
+  if(CMAKE_BUILD_TYPE STREQUAL "Debug"
+     AND DEFINED ${_Python}_EXECUTABLE_DEBUG
+     AND IS_EXECUTABLE ${${_Python}_EXECUTABLE_DEBUG})
+    set(PYBIND11_PYTHON_EXECUTABLE_LAST
+        "${${_Python}_EXECUTABLE_DEBUG}"
+        CACHE INTERNAL "Python executable during the last CMake run")
+  else()
+    set(PYBIND11_PYTHON_EXECUTABLE_LAST
+        "${${_Python}_EXECUTABLE}"
+        CACHE INTERNAL "Python executable during the last CMake run")
+  endif()
 
   if(NOT DEFINED PYTHON_IS_DEBUG)
     # Debug check - see https://stackoverflow.com/questions/646518/python-how-to-detect-debug-Interpreter
     execute_process(
-      COMMAND "${${_Python}_EXECUTABLE}" "-c"
+      COMMAND "${PYBIND11_PYTHON_EXECUTABLE_LAST}" "-c"
               "import sys; sys.exit(hasattr(sys, 'gettotalrefcount'))"
       RESULT_VARIABLE _PYTHON_IS_DEBUG)
     set(PYTHON_IS_DEBUG
@@ -145,7 +153,7 @@ if(NOT _PYBIND11_CROSSCOMPILING)
   if(NOT DEFINED PYTHON_MODULE_EXTENSION OR NOT DEFINED PYTHON_MODULE_DEBUG_POSTFIX)
     execute_process(
       COMMAND
-        "${${_Python}_EXECUTABLE}" "-c"
+        "${PYBIND11_PYTHON_EXECUTABLE_LAST}" "-c"
         "import sys, importlib; s = importlib.import_module('distutils.sysconfig' if sys.version_info < (3, 10) else 'sysconfig'); print(s.get_config_var('EXT_SUFFIX') or s.get_config_var('SO'))"
       OUTPUT_VARIABLE _PYTHON_MODULE_EXT_SUFFIX
       ERROR_VARIABLE _PYTHON_MODULE_EXT_SUFFIX_ERR