*A group of physical trainers are suing Oprah Winfrey and her Harpo Inc. for non-payment, however, their legal action may be foiled by clause in the contract they signed, and which is now posted at TMZ.com

According to the Web site, Unicus Performance Training filed the lawsuit earlier this week, claiming they never received payment for a workout program they were developing for Harpo.

UPT says Harpo fired them for violating the terms of their confidentiality agreement, after UPT sent out a mass e-mail promoting their upcoming appearance on Oprah’s radio show.

According the confidentiality agreement, UPT was forbidden to “use HARPO’s name, Oprah.com’s name or Ms. Winfrey’s name” for any advertising or promotional purposes.

The document bars UPT from saying anything at anytime about Winfrey and Harpo without “express, written permission.”