diff --git a/git-format-patch.sh b/git-format-patch.sh
index 4cd38f34e..1eebe857c 100755
--- a/git-format-patch.sh
+++ b/git-format-patch.sh
@@ -5,6 +5,10 @@
 
 . git-sh-setup
 
+# Force diff to run in C locale.
+LANG=C LC_ALL=C
+export LANG LC_ALL
+
 usage () {
     echo >&2 "usage: $0"' [-n] [-o dir | --stdout] [--keep-subject] [--mbox]
     [--check] [--signoff] [-<diff options>...]
@@ -202,7 +206,7 @@ process_one () {
 	    ;;
 	esac
 
-	eval "$(LANG=C LC_ALL=C sed -ne "$whosepatchScript" $commsg)"
+	eval "$(sed -ne "$whosepatchScript" $commsg)"
 	test "$author,$au" = ",$me" || {
 		mailScript="$mailScript"'
 	a\