diff --git a/src/list.c b/src/list.c
index b593f71..1dfaa21 100644
--- a/src/list.c
+++ b/src/list.c
@@ -475,6 +475,27 @@
 }
 
 /*
+ * Append list2 to list1.
+ * Return FAIL when out of memory.
+ */
+    int
+list_append_list(list1, list2)
+    list_T	*list1;
+    list_T	*list2;
+{
+    listitem_T	*li = listitem_alloc();
+
+    if (li == NULL)
+	return FAIL;
+    li->li_tv.v_type = VAR_LIST;
+    li->li_tv.v_lock = 0;
+    li->li_tv.vval.v_list = list2;
+    list_append(list1, li);
+    ++list2->lv_refcount;
+    return OK;
+}
+
+/*
  * Make a copy of "str" and append it as an item to list "l".
  * When "len" >= 0 use "str[len]".
  * Returns FAIL when out of memory.