We'll detail everything you need to know about how to invite a guest speaker, from the earliest planning stages to drafting a formal speaker invitation letter. On behalf of the XYZ and the XYZ Organizing Committee, we are honored to invite you to speak at the XYZ event celebrating Cybersecurity Career Week (CCW).Begin with a Polite Greeting. You should include the name of the host, formal expression, the event purpose, date, time, and venue, contact details, and RSVP. Write your reason for inviting them to be your "chief guest. " Tell them if they will be expected to speak to the group and if so, for how long. Your invitation should be a formal email (or letter). Outline the reasons why you've chosen them as the best person to speak at your event. Sample Template for Inviting a Guest Speaker. A great sample of an invitation letter for a guest speaker.