diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index d56426dd39..cf864a6273 100755
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -159,6 +159,13 @@ get_author_ident_from_commit () {
 	LANG=C LC_ALL=C sed -ne "$pick_author_script"
 }
 
+# Clear repo-local GIT_* environment variables. Useful when switching to
+# another repository (e.g. when entering a submodule). See also the env
+# list in git_connect()
+clear_local_git_env() {
+	unset $(git rev-parse --local-env-vars)
+}
+
 # Make sure we are in a valid repository of a vintage we understand,
 # if we require to be in a git repository.
 if test -z "$NONGIT_OK"