diff --git a/lisp/use-package/use-package.el b/lisp/use-package/use-package.el
index f36cebe70d1..5b732c12179 100644
--- a/lisp/use-package/use-package.el
+++ b/lisp/use-package/use-package.el
@@ -1482,10 +1482,12 @@ deferred until the prefix key sequence is pressed."
      SYMBOL
      (SYMBOL . STRING)"
   (cond
+   ((not arg)
+    (list (use-package-as-mode name)))
    ((symbolp arg)
     (list arg))
    ((stringp arg)
-    (list (cons (intern (concat (use-package-as-string name) "-mode")) arg)))
+    (list (cons (use-package-as-mode name) arg)))
    ((and (consp arg) (stringp (cdr arg)))
     (list arg))
    ((and (not recursed) (listp arg) (listp (cdr arg)))
diff --git a/test/lisp/use-package/use-package-tests.el b/test/lisp/use-package/use-package-tests.el
index 625e95ca587..c52c3810439 100644
--- a/test/lisp/use-package/use-package-tests.el
+++ b/test/lisp/use-package/use-package-tests.el
@@ -72,6 +72,18 @@
 
   )
 
+(ert-deftest use-package-normalize-diminish ()
+  (should (equal (use-package-normalize-diminish 'foopkg :diminish nil)
+                 '(foopkg-mode)))
+  (should (equal (use-package-normalize-diminish 'foopkg :diminish 'bar)
+                 '(bar)))
+  (should (equal (use-package-normalize-diminish 'foopkg :diminish "bar")
+                 '((foopkg-mode . "bar"))))
+  (should (equal (use-package-normalize-diminish 'foopkg :diminish 'foo-mode)
+                 '(foo-mode)))
+  (should (equal (use-package-normalize-diminish 'foopkg :diminish '(foo . "bar"))
+                 '((foo . "bar")))))
+
 ;; Local Variables:
 ;; indent-tabs-mode: nil
 ;; no-byte-compile: t