diff --git a/Tools/buildbot/build-amd64.bat b/Tools/buildbot/build-amd64.bat
index 7ee7b2d9b36..569c4517a25 100644
--- a/Tools/buildbot/build-amd64.bat
+++ b/Tools/buildbot/build-amd64.bat
@@ -1,4 +1,5 @@
 @rem Used by the buildbot "compile" step.
+set HOST_PYTHON=%CD%\PCbuild\amd64\python_d.exe
 cmd /c Tools\buildbot\external-amd64.bat
 call "%VS100COMNTOOLS%\..\..\VC\vcvarsall.bat" x86_amd64
 cmd /c Tools\buildbot\clean-amd64.bat