Yes. A U.S. petitioner is mandatory for an O-1B.The petitioner can be either a U.S. employer, such as an agency or production company, or a U.S. agent representing you for freelance or project-based work.The petitioner signs and files the forms on your behalf; you cannot self-petition or sign for yourself.When using an agent, the agent submits a proposed itinerary and evidence of engagements in the U.S. to show USCIS that you have legitimate, pre-arranged work, even if you are not tied to a single U.S. employer.