diff --git a/app/helpers/instance_helper.rb b/app/helpers/instance_helper.rb
index dd0b25f3e..daacb535b 100644
--- a/app/helpers/instance_helper.rb
+++ b/app/helpers/instance_helper.rb
@@ -8,4 +8,16 @@ module InstanceHelper
   def site_hostname
     @site_hostname ||= Addressable::URI.parse("//#{Rails.configuration.x.local_domain}").display_uri.host
   end
+
+  def description_for_sign_up
+    prefix = begin
+      if @invite.present?
+        I18n.t('auth.description.prefix_invited_by_user', name: @invite.user.account.username)
+      else
+        I18n.t('auth.description.prefix_sign_up')
+      end
+    end
+
+    safe_join([prefix, I18n.t('auth.description.suffix')], ' ')
+  end
 end
diff --git a/app/views/auth/registrations/new.html.haml b/app/views/auth/registrations/new.html.haml
index 83384d737..e807c8d86 100644
--- a/app/views/auth/registrations/new.html.haml
+++ b/app/views/auth/registrations/new.html.haml
@@ -2,7 +2,7 @@
   = t('auth.register')
 
 - content_for :header_tags do
-  = render partial: 'shared/og'
+  = render partial: 'shared/og', locals: { description: description_for_sign_up }
 
 = simple_form_for(resource, as: resource_name, url: registration_path(resource_name)) do |f|
   = render 'shared/error_messages', object: resource
diff --git a/app/views/shared/_og.html.haml b/app/views/shared/_og.html.haml
index 67238fc8b..576f47a67 100644
--- a/app/views/shared/_og.html.haml
+++ b/app/views/shared/_og.html.haml
@@ -1,5 +1,5 @@
-- thumbnail = @instance_presenter.thumbnail
-- description = strip_tags(@instance_presenter.site_short_description.presence || @instance_presenter.site_description.presence || t('about.about_mastodon_html'))
+- thumbnail     = @instance_presenter.thumbnail
+- description ||= strip_tags(@instance_presenter.site_short_description.presence || @instance_presenter.site_description.presence || t('about.about_mastodon_html'))
 
 %meta{ name: 'description', content: description }/
 
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 9c9dbc94b..ad29e0a74 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -569,6 +569,10 @@ en:
     checkbox_agreement_without_rules_html: I agree to the <a href="%{terms_path}" target="_blank">terms of service</a>
     delete_account: Delete account
     delete_account_html: If you wish to delete your account, you can <a href="%{path}">proceed here</a>. You will be asked for confirmation.
+    description:
+      prefix_invited_by_user: "@%{name} invites you to join this server of Mastodon!"
+      prefix_sign_up: Sign up on Mastodon today!
+      suffix: With an account, you will be able to follow people, post updates and exchange messages with users from any Mastodon server and more!
     didnt_get_confirmation: Didn't receive confirmation instructions?
     forgot_password: Forgot your password?
     invalid_reset_password_token: Password reset token is invalid or expired. Please request a new one.