diff --git a/builtin/describe.c b/builtin/describe.c
index 02ec564..1409ced 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -630,6 +630,7 @@
 			struct argv_array args = ARGV_ARRAY_INIT;
 			int fd, result;
 
+			setup_work_tree();
 			read_cache();
 			refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED,
 				      NULL, NULL, NULL);
diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh
index d639d94..ee5b03e 100755
--- a/t/t6120-describe.sh
+++ b/t/t6120-describe.sh
@@ -143,16 +143,46 @@
 test_expect_success 'pack tag refs' 'git pack-refs'
 check_describe A-* HEAD
 
+test_expect_success 'describe works from outside repo using --git-dir' '
+	git clone --bare "$TRASH_DIRECTORY" "$TRASH_DIRECTORY/bare" &&
+	git --git-dir "$TRASH_DIRECTORY/bare" describe >out &&
+	grep "^A-[1-9][0-9]\?-g[0-9a-f]\+$" out
+'
+
 check_describe "A-*[0-9a-f]" --dirty
 
+test_expect_success 'describe --dirty with --work-tree' '
+	(
+		cd "$TEST_DIRECTORY" &&
+		git --git-dir "$TRASH_DIRECTORY/.git" --work-tree "$TRASH_DIRECTORY" describe --dirty >"$TRASH_DIRECTORY/out"
+	) &&
+	grep "^A-[1-9][0-9]\?-g[0-9a-f]\+$" out
+'
+
 test_expect_success 'set-up dirty work tree' '
 	echo >>file
 '
 
 check_describe "A-*[0-9a-f]-dirty" --dirty
 
+test_expect_success 'describe --dirty with --work-tree (dirty)' '
+	(
+		cd "$TEST_DIRECTORY" &&
+		git --git-dir "$TRASH_DIRECTORY/.git" --work-tree "$TRASH_DIRECTORY" describe --dirty >"$TRASH_DIRECTORY/out"
+	) &&
+	grep "^A-[1-9][0-9]\?-g[0-9a-f]\+-dirty$" out
+'
+
 check_describe "A-*[0-9a-f].mod" --dirty=.mod
 
+test_expect_success 'describe --dirty=.mod with --work-tree (dirty)' '
+	(
+		cd "$TEST_DIRECTORY" &&
+		git --git-dir "$TRASH_DIRECTORY/.git" --work-tree "$TRASH_DIRECTORY" describe --dirty=.mod >"$TRASH_DIRECTORY/out"
+	) &&
+	grep "^A-[1-9][0-9]\?-g[0-9a-f]\+.mod$" out
+'
+
 test_expect_success 'describe --dirty HEAD' '
 	test_must_fail git describe --dirty HEAD
 '
@@ -303,8 +333,17 @@
 	mv .git/modules/sub1/ .git/modules/sub_moved &&
 	test_must_fail git describe --dirty
 '
+
 test_expect_success 'describe ignoring a broken submodule' '
 	git describe --broken >out &&
+	grep broken out
+'
+
+test_expect_success 'describe with --work-tree ignoring a broken submodule' '
+	(
+		cd "$TEST_DIRECTORY" &&
+		git --git-dir "$TRASH_DIRECTORY/.git" --work-tree "$TRASH_DIRECTORY" describe --broken >"$TRASH_DIRECTORY/out"
+	) &&
 	test_when_finished "mv .git/modules/sub_moved .git/modules/sub1" &&
 	grep broken out
 '