--- a/lisp/facemenu.el
+++ b/lisp/facemenu.el
@@ -702,6 +702,9 @@ defun facemenu-add-face (face &optional start end)
 text property.  Otherwise, selecting the default face would not have any
 effect.  See `facemenu-remove-face-function'."
   (interactive "*xFace: \nr")
+  (when (stringp face)
+    (warn "Face %S is a string; interning" face)
+    (setq face (intern face)))
   (cond
    ((and (eq face 'default)
          (not (eq facemenu-remove-face-function t)))
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -402,6 +402,9 @@ defun face-attribute (face attribute &optional frame inherit)
 value of `default' for INHERIT; this will resolve any unspecified or
 relative values by merging with the `default' face (which is always
 completely specified)."
+  (when (stringp face)
+    (message "Face %S is a string; interning" face)
+    (setq face (intern face)))
   (let ((value (internal-get-lisp-face-attribute face attribute frame)))
     (when (and inherit (face-attribute-relative-p attribute value))
       ;; VALUE is relative, so merge with inherited faces