diff --git a/Modules/FindPythonInterp.cmake b/Modules/FindPythonInterp.cmake
index 128dcd5fd..d5a2a5e92 100644
--- a/Modules/FindPythonInterp.cmake
+++ b/Modules/FindPythonInterp.cmake
@@ -89,11 +89,15 @@ endif()
 # determine python version string
 if(PYTHON_EXECUTABLE)
     execute_process(COMMAND "${PYTHON_EXECUTABLE}" --version ERROR_VARIABLE _VERSION OUTPUT_QUIET ERROR_STRIP_TRAILING_WHITESPACE)
-    string(REPLACE "Python " "" PYTHON_VERSION_STRING "${_VERSION}")
-    string(REGEX REPLACE "^([0-9]+)\\.[0-9]+\\.[0-9]+.*" "\\1" PYTHON_VERSION_MAJOR "${PYTHON_VERSION_STRING}")
-    string(REGEX REPLACE "^[0-9]+\\.([0-9])+\\.[0-9]+.*" "\\1" PYTHON_VERSION_MINOR "${PYTHON_VERSION_STRING}")
-    string(REGEX REPLACE "^[0-9]+\\.[0-9]+\\.([0-9]+).*" "\\1" PYTHON_VERSION_PATCH "${PYTHON_VERSION_STRING}")
-endif()
+    if(_VERSION MATCHES "^Python [0-9]+\\.[0-9]+.*")
+        string(REPLACE "Python " "" PYTHON_VERSION_STRING "${_VERSION}")
+        string(REGEX REPLACE "^([0-9]+)\\.[0-9]+.*" "\\1" PYTHON_VERSION_MAJOR "${PYTHON_VERSION_STRING}")
+        string(REGEX REPLACE "^[0-9]+\\.([0-9])+.*" "\\1" PYTHON_VERSION_MINOR "${PYTHON_VERSION_STRING}")
+        if(PYTHON_VERSION_STRING MATCHES "^[0-9]+\\.[0-9]+\\.[0-9]+.*")
+            string(REGEX REPLACE "^[0-9]+\\.[0-9]+\\.([0-9]+).*" "\\1" PYTHON_VERSION_PATCH "${PYTHON_VERSION_STRING}")
+        endif()
+    endif()
+endif(PYTHON_EXECUTABLE)
 
 # handle the QUIETLY and REQUIRED arguments and set PYTHONINTERP_FOUND to TRUE if
 # all listed variables are TRUE