diff --git a/app/models/translation_override.rb b/app/models/translation_override.rb
index 1f217e9f847..1071d5dd2f0 100644
--- a/app/models/translation_override.rb
+++ b/app/models/translation_override.rb
@@ -9,6 +9,13 @@ class TranslationOverride < ActiveRecord::Base
       topic_title_url_encoded
       site_title_url_encoded
       context
+
+      site_name
+      optional_re
+      optional_pm
+      optional_cat
+      optional_tags
+      topic_title
     }
   }
   include ActiveSupport::Deprecation::DeprecatedConstantAccessor
diff --git a/lib/email/message_builder.rb b/lib/email/message_builder.rb
index 463e9c08684..fa42814bb24 100644
--- a/lib/email/message_builder.rb
+++ b/lib/email/message_builder.rb
@@ -53,7 +53,15 @@ module Email
     def subject
       if @opts[:template] &&
           TranslationOverride.exists?(locale: I18n.locale, translation_key: "#{@opts[:template]}.subject_template")
-        subject = I18n.t("#{@opts[:template]}.subject_template", @template_args)
+        augmented_template_args = @template_args.merge({
+          site_name: @template_args[:email_prefix],
+          optional_re: @opts[:add_re_to_subject] ? I18n.t('subject_re') : '',
+          optional_pm: @opts[:private_reply] ? @template_args[:subject_pm] : '',
+          optional_cat: @template_args[:show_category_in_subject] ? "[#{@template_args[:show_category_in_subject]}] " : '',
+          optional_tags: @template_args[:show_tags_in_subject] ? "#{@template_args[:show_tags_in_subject]} " : '',
+          topic_title: @template_args[:topic_title] ? @template_args[:topic_title] : '',
+        })
+        subject = I18n.t("#{@opts[:template]}.subject_template", augmented_template_args)
       elsif @opts[:use_site_subject]
         subject = String.new(SiteSetting.email_subject)
         subject.gsub!("%{site_name}", @template_args[:email_prefix])
diff --git a/spec/components/email/message_builder_spec.rb b/spec/components/email/message_builder_spec.rb
index 939257d201b..9043652b7c1 100644
--- a/spec/components/email/message_builder_spec.rb
+++ b/spec/components/email/message_builder_spec.rb
@@ -258,17 +258,28 @@ describe Email::MessageBuilder do
     end
 
     context "when use_site_subject is true" do
-      let(:templated_builder) { Email::MessageBuilder.new(to_address, template: 'mystery', use_site_subject: true) }
+      let(:templated_builder) { Email::MessageBuilder.new(to_address, template: 'user_notifications.user_replied', use_site_subject: true, topic_title: "Topic Title") }
 
       it "can use subject override" do
-        override = TranslationOverride.create(
-          locale: I18n.locale,
-          translation_key: "mystery.subject_template",
-          value: "my customized subject"
+        override = TranslationOverride.upsert!(
+          I18n.locale,
+          "user_notifications.user_replied.subject_template",
+          "my customized subject"
         )
-        I18n.expects(:t).with("mystery.subject_template", templated_builder.template_args).returns(override.value)
+        override.save!
         expect(templated_builder.subject).to eq(override.value)
       end
+
+      it "can use interpolation arguments in the override" do
+        SiteSetting.email_prefix = 'some email prefix'
+        override = TranslationOverride.upsert!(
+          I18n.locale,
+          "user_notifications.user_replied.subject_template",
+          "[%{site_name}] %{topic_title} my customized subject"
+        ).save!
+        expect(templated_builder.subject).to match("some email prefix")
+        expect(templated_builder.subject).to match("customized subject")
+      end
     end
 
   end