diff --git a/beets/library.py b/beets/library.py
index d0571ed3a..bbb6452fe 100644
--- a/beets/library.py
+++ b/beets/library.py
@@ -1506,9 +1506,16 @@ class DefaultTemplateFunctions(object):
         # Fast paths: no album, no item or library, or memoized value.
         if not self.item or not self.lib:
             return u''
-        if self.item.album_id is None:
+
+        if isinstance(self.item, Item):
+            album_id = self.item.album_id
+        elif isinstance(self.item, Album):
+            album_id = self.item.id
+
+        if album_id is None:
             return u''
-        memokey = ('aunique', keys, disam, self.item.album_id)
+
+        memokey = ('aunique', keys, disam, album_id)
         memoval = self.lib._memotable.get(memokey)
         if memoval is not None:
             return memoval
@@ -1528,7 +1535,7 @@ class DefaultTemplateFunctions(object):
             bracket_l = u''
             bracket_r = u''
 
-        album = self.lib.get_album(self.item)
+        album = self.lib.get_album(album_id)
         if not album:
             # Do nothing for singletons.
             self.lib._memotable[memokey] = u''
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 2b8ede053..7081a2ddb 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -92,6 +92,9 @@ Fixes:
   :bug:`2504` :bug:`3029`
 * Avoid a crash when archive extraction fails during import.
   :bug:`3041`
+* The ``%aunique`` template function now works correctly with the
+  ``-f/--format`` option.
+  :bug:`3043`
 
 .. _python-itunes: https://github.com/ocelma/python-itunes