diff --git a/actionpack/lib/action_dispatch/http/mime_negotiation.rb b/actionpack/lib/action_dispatch/http/mime_negotiation.rb

index 53a98c5d0a..00fd3d03df 100644

--- a/actionpack/lib/action_dispatch/http/mime_negotiation.rb

+++ b/actionpack/lib/action_dispatch/http/mime_negotiation.rb

@@ -61,7 +61,7 @@ module ActionDispatch

                               false

                             end

-          if params_readable

+          v = if params_readable

             Array(Mime[parameters[:format]])

           elsif use_accept_header && valid_accept_header

             accepts

@@ -70,6 +70,10 @@ module ActionDispatch

           else

             [Mime::HTML]

           end

+

+          v.select do |format|

+            format.symbol || format.ref == "*/*"

+          end

         end

       end