diff --git a/pipenv/utils.py b/pipenv/utils.py
index 6380b173..2e713915 100644
--- a/pipenv/utils.py
+++ b/pipenv/utils.py
@@ -55,7 +55,7 @@ class HackedPythonVersion(object):
 
     def __enter__(self):
         if self.python:
-            os.environ['PIP_PYTHON_VERSION'] = self.python
+            os.environ['PIP_PYTHON_VERSION'] = str(self.python)
 
     def __exit__(self, *args):
         # Restore original Python version information.