Paris Hilton leaves federal court in Miami, Thursday, July 9, 2009. Hilton is accused in a federal lawsuit of failing to adequately promote her 2006 movie 'Pledge This!.' [Agencies]

MIAMI – Paris Hilton hated her 2006 movie "Pledge This!" and refused for months to make promotional appearances for it despite a contract requiring her to do so, lawyers for the film's investors said as trial opened Thursday in an $8 million lawsuit against her.

"During the six-month period, at no time would she take 10 minutes to do a phone interview," attorney Bryan West, who represents the investors, said in opening statements.

With Hilton nodding vigorously from her defense table seat, her attorney Michael Weinsten insisted she did numerous appearances for the movie but was unavailable to meet many requests by the film's producers because of her extremely busy schedule. Hilton also had the right to refuse some promotion events that might harm her "brand" and never agreed to plug the DVD release of the movie from December 2006 through May 2007, he said.

"Paris Hilton is a promotion machine," Weinsten said. "For 2 1/2 years, she relentlessly promoted that movie."

One of the movie's executive producers, James DiLorenzo, testified that Hilton's handlers rejected a series of suggested promotion efforts, including popular late-night TV talk shows and interviews with magazines, newspapers and radio outlets in the U.S. and abroad.

"In order to make the public aware of the product, she was the most powerful way of doing that," DiLorenzo said.

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Hilton, a 28-year-old heiress, actress and model, is expected to testify Friday. She traveled to Miami for the trial from Dubai, where she has been filming episodes of her "My New BFF" reality show. Wearing a sleeveless black-and-white dress with a large bow on the back, Hilton sat quietly at the defense table during opening statements, occasionally taking notes or fiddling with her twin ponytails.

The lawsuit is being heard by Chief U.S. District Judge Federico Moreno, who has a well known sense of humor. Moreno at one point asked West whether the contract allowed Hilton to refuse even the most outrageous promotion requests.

"If you said, 'She has to parade nude down the Champs-Elysees with a Pledge This! banner' ... and she said no, would that be breach of contract?" Moreno asked. Then, answering his own question, he added, "No, of course not."