diff --git a/lib/devise/mapping.rb b/lib/devise/mapping.rb
index 27d5e08b..4d6c92fb 100644
--- a/lib/devise/mapping.rb
+++ b/lib/devise/mapping.rb
@@ -58,6 +58,7 @@ module Devise
       mod = options[:module] || "devise"
       @controllers = Hash.new { |h,k| h[k] = "#{mod}/#{k}" }
       @controllers.merge!(options[:controllers] || {})
+      @controllers.each { |k,v| @controllers[k] = v.to_s }
 
       @path_names = Hash.new { |h,k| h[k] = k.to_s }
       @path_names.merge!(:registration => "")
diff --git a/test/rails_app/config/routes.rb b/test/rails_app/config/routes.rb
index 312503cd..b6768d7b 100644
--- a/test/rails_app/config/routes.rb
+++ b/test/rails_app/config/routes.rb
@@ -19,7 +19,7 @@ Rails.application.routes.draw do
   match "/sign_in", :to => "devise/sessions#new"
 
   # Admin scope
-  devise_for :admin, :path => "admin_area", :controllers => { :sessions => "admins/sessions" }, :skip => :passwords
+  devise_for :admin, :path => "admin_area", :controllers => { :sessions => :"admins/sessions" }, :skip => :passwords
 
   match "/admin_area/home", :to => "admins#index", :as => :admin_root
   match "/anywhere", :to => "foo#bar", :as => :new_admin_password