diff --git a/awsshell/app.py b/awsshell/app.py
index 84b5660..3194351 100644
--- a/awsshell/app.py
+++ b/awsshell/app.py
@@ -507,6 +507,6 @@ def profile(self, new_profile_name):
         # it's worth adding an event system or observers just yet.
         # If this gets hard to manage, the complexity of those systems
         # would be worth it.
-        self._env['AWS_DEFAULT_PROFILE'] = new_profile_name
+        self._env[str('AWS_DEFAULT_PROFILE')] = new_profile_name
         self.completer.change_profile(new_profile_name)
         self._profile = new_profile_name