Jessica Simpson at The 2006 CFDA Fashion Awards at the New York Public Library. New York City, USA - 05.06.06

Simpson was represented by Joel, who works for high-powered Hollywood agency CAA, for several years and is now being represented by RICK NICITA, also of CAA.

A source tells American publication Us Weekly, "Brandt got into a huge fight with Joe Simpson.

"Joe is constantly trying to butt in and he doesn't know what the hell he is doing. Jessica took her father's side and fired him."