diff --git a/src/calibre/db/cache.py b/src/calibre/db/cache.py
index be3a5ab5fb..bbf8858241 100644
--- a/src/calibre/db/cache.py
+++ b/src/calibre/db/cache.py
@@ -1448,15 +1448,15 @@ class Cache(object):
         return _get_next_series_num_for_list(tuple(series_indices), unwrap=False)
 
     @read_api
-    def author_sort_from_authors(self, authors):
+    def author_sort_from_authors(self, authors, key_func=icu_lower):
         '''Given a list of authors, return the author_sort string for the authors,
         preferring the author sort associated with the author over the computed
         string. '''
         table = self.fields['authors'].table
         result = []
-        rmap = {icu_lower(v):k for k, v in table.id_map.iteritems()}
+        rmap = {key_func(v):k for k, v in table.id_map.iteritems()}
         for aut in authors:
-            aid = rmap.get(icu_lower(aut), None)
+            aid = rmap.get(key_func(aut), None)
             result.append(author_to_author_sort(aut) if aid is None else table.asort_map[aid])
         return ' & '.join(filter(None, result))
 
diff --git a/src/calibre/db/legacy.py b/src/calibre/db/legacy.py
index 7e51abd317..ad6541bc79 100644
--- a/src/calibre/db/legacy.py
+++ b/src/calibre/db/legacy.py
@@ -903,7 +903,7 @@ LibraryDatabase.metadata_for_field = MT(lambda self, field:self.field_metadata.g
 # }}}
 
 # Miscellaneous API {{{
-for meth in ('get_next_series_num_for', 'has_book', 'author_sort_from_authors'):
+for meth in ('get_next_series_num_for', 'has_book',):
     def getter(meth):
         def func(self, x):
             return getattr(self.new_api, meth)(x)
@@ -917,6 +917,7 @@ LibraryDatabase.saved_search_delete = MT(lambda self, x:self.new_api.saved_searc
 LibraryDatabase.saved_search_add = MT(lambda self, x, y:self.new_api.saved_search_add(x, y))
 LibraryDatabase.saved_search_rename = MT(lambda self, x, y:self.new_api.saved_search_rename(x, y))
 LibraryDatabase.commit_dirty_cache = MT(lambda self: self.new_api.commit_dirty_cache())
+LibraryDatabase.author_sort_from_authors = MT(lambda self, x: self.new_api.author_sort_from_authors(x))
 # Cleaning is not required anymore
 LibraryDatabase.clean = LibraryDatabase.clean_custom = MT(lambda self:None)
 LibraryDatabase.clean_standard_field = MT(lambda self, field, commit=False:None)
diff --git a/src/calibre/gui2/metadata/basic_widgets.py b/src/calibre/gui2/metadata/basic_widgets.py
index 4c15363dfe..9df65d453a 100644
--- a/src/calibre/gui2/metadata/basic_widgets.py
+++ b/src/calibre/gui2/metadata/basic_widgets.py
@@ -486,10 +486,13 @@ class AuthorSortEdit(EnLineEdit, ToMetadataMixin):
         self.first_time = False
         self.update_state()
 
+    def author_sort_from_authors(self, authors):
+        return self.db.new_api.author_sort_from_authors(authors, key_func=lambda x: x)
+
     def update_state(self, *args):
         au = unicode(self.authors_edit.text())
         au = re.sub(r'\s+et al\.$', '', au)
-        au = self.db.author_sort_from_authors(string_to_authors(au))
+        au = self.author_sort_from_authors(string_to_authors(au))
 
         normal = au == self.current_val
         col = OK_COLOR if normal else ERR_COLOR
@@ -517,7 +520,7 @@ class AuthorSortEdit(EnLineEdit, ToMetadataMixin):
         au = unicode(self.authors_edit.text())
         au = re.sub(r'\s+et al\.$', '', au).strip()
         authors = string_to_authors(au)
-        self.current_val = self.db.author_sort_from_authors(authors)
+        self.current_val = self.author_sort_from_authors(authors)
 
     def author_to_sort(self, *args):
         au = unicode(self.authors_edit.text())