The 86-year-old Horne reportedly is angry about Jackson's breast-baring stunt at Super Bowl (search) and pressured ABC to drop Jackson from the project, the trade newspaper Variety reported Tuesday.
Producers Craig Zadan and Neil Meron, who also produced the TV bios "The Three Stooges," "Martin and Lewis" and the controversial "The Reagans," also quit the project in solidarity with Jackson, Variety added.
ABC executives resisted Horne's demand, but Jackson representatives told the trade newspaper that she left willingly after Horne and her daughter, Gail Lumet Buckley, asked that she not take part.
The network wouldn't comment on the film Tuesday.
In addition to her work as a pop musician, Jackson also has acted in the films "Poetic Justice" and "Nutty Professor II: The Klumps." She was recently photographed in makeup designed to mimic Horne in a Vanity Fair photo spread.