Make a custom helper available to both Mailer and View in Rails 3.1

is this the best way to make a helper available to both Mailer and view in Rails 3.1?

class EventMailer < ActionMailer::Base
  include MailerHelper
  helper :mailer

I tried

helper :mailer

on its own, but that didn't allow me to use the helpers in the EventMailer class.

I tried

add_template_helper(MailerHelper)

but had the same problem.