diff --git a/lib/sidekiq/core_ext.rb b/lib/sidekiq/core_ext.rb
index ca9009df..80276d2d 100644
--- a/lib/sidekiq/core_ext.rb
+++ b/lib/sidekiq/core_ext.rb
@@ -51,4 +51,34 @@ rescue LoadError
   end
 end
 
+begin
+  require 'active_support/core_ext/hash/keys'
+rescue LoadError
+  class Hash
+    def stringify_keys(hash)
+      hash.keys.each do |key|
+        hash[key.to_s] = hash.delete(key)
+      end
+      hash
+    end
+  end if !{}.responds_to(:stringify_keys)
+end
+
+begin
+  require 'active_support/core_ext/string/inflections'
+rescue LoadError
+  class String
+    def constantize
+      names = self.split('::')
+      names.shift if names.empty? || names.first.empty?
+
+      constant = Object
+      names.each do |name|
+        constant = constant.const_defined?(name) ? constant.const_get(name) : constant.const_missing(name)
+      end
+      constant
+    end
+  end if !"".responds_to(:constantize)
+end
+
 
diff --git a/lib/sidekiq/processor.rb b/lib/sidekiq/processor.rb
index 605626e5..4249fd30 100644
--- a/lib/sidekiq/processor.rb
+++ b/lib/sidekiq/processor.rb
@@ -34,7 +34,7 @@ module Sidekiq
       defer do
         begin
           msg = Sidekiq.load_json(msgstr)
-          klass  = constantize(msg['class'])
+          klass  = msg['class'].constantize
           worker = klass.new
 
           stats(worker, msg, queue) do
diff --git a/lib/sidekiq/util.rb b/lib/sidekiq/util.rb
index ffc5151f..819bb709 100644
--- a/lib/sidekiq/util.rb
+++ b/lib/sidekiq/util.rb
@@ -1,5 +1,6 @@
 require 'socket'
 require 'sidekiq/exception_handler'
+require 'sidekiq/core_ext'
 
 module Sidekiq
   ##
@@ -10,17 +11,6 @@ module Sidekiq
 
     EXPIRY = 60 * 60 * 24
 
-    def constantize(camel_cased_word)
-      names = camel_cased_word.split('::')
-      names.shift if names.empty? || names.first.empty?
-
-      constant = Object
-      names.each do |name|
-        constant = constant.const_defined?(name) ? constant.const_get(name) : constant.const_missing(name)
-      end
-      constant
-    end
-
     def watchdog(last_words)
       yield
     rescue Exception => ex
diff --git a/lib/sidekiq/worker.rb b/lib/sidekiq/worker.rb
index 080ab36c..be569a0c 100644
--- a/lib/sidekiq/worker.rb
+++ b/lib/sidekiq/worker.rb
@@ -31,6 +31,7 @@ module Sidekiq
     end
 
     module ClassMethods
+
       def perform_async(*args)
         client_push('class' => self, 'args' => args)
       end
@@ -52,7 +53,7 @@ module Sidekiq
       #   :backtrace - whether to save any error backtrace in the retry payload to display in web UI,
       #      can be true, false or an integer number of lines to save, default *false*
       def sidekiq_options(opts={})
-        self.sidekiq_options_hash = get_sidekiq_options.merge(stringify_keys(opts || {}))
+        self.sidekiq_options_hash = get_sidekiq_options.merge((opts || {}).stringify_keys)
       end
 
       DEFAULT_OPTIONS = { 'retry' => true, 'queue' => 'default' }
@@ -61,15 +62,8 @@ module Sidekiq
         self.sidekiq_options_hash ||= DEFAULT_OPTIONS
       end
 
-      def stringify_keys(hash) # :nodoc:
-        hash.keys.each do |key|
-          hash[key.to_s] = hash.delete(key)
-        end
-        hash
-      end
-
       def client_push(item) # :nodoc:
-        Sidekiq::Client.push(stringify_keys(item))
+        Sidekiq::Client.push(item.stringify_keys)
       end
 
     end