Michael Corrente said yesterday that he will begin shooting his long-planned film about former Providence Mayor Vincent A. Cianci Jr. in August in Rhode Island.

But Cianci in a later interview said he was in negotiations with a production company to do a competing, authorized movie about his life.

Corrente verified a report that appeared in yesterday’s Hollywood Reporter that Oliver Platt will play the former mayor. He also confirmed that he is in talks with Robin Williams for a supporting role and that director Steven Soderbergh, whose films include Ocean’s Eleven and Ocean’s Twelve, would be the executive producer of The Prince of Providence.

The film, which Corrente will direct, is based on the best-selling book by Providence Journal reporter Mike Stanton. David Mamet, a Pultizer-Prize winning playwright, wrote the screenplay, with writing credit going to Howard Korder for his services on a polished draft.

Cianci, reached by phone during a break from his radio talk show on WPRO, said he had “been in negotiations for about a year” with Tribeca Productions, the New York-based company founded by Robert De Niro and Jane Rosenthal, who grew up in Providence. “They approached me. I said yes, go ahead with it.”

Cianci said work on “the screenplay is in progress.”

However, Tammy Rosen, spokeswoman for Tribeca in New York, said in a phone interview that the Cianci film is “just a verbal commitment” at this point and that the paperwork has not been completed.

Nevertheless, she added that “we’re looking at attaching writers to the script now.” Cianci said he has met with some of the writers who are being considered.

Rosen emphasized that Tribeca “very much wanted” to bring “the story of America’s most notorious mayor” to the screen and wanted to have Cianci’s “unique voice” as part of the project.

Rosen said it’s not unusual to have competing film projects in the works on the same subject.

Cianci also said he was in the process of working on a book about his life with a writer he declined to name. “I’ll be making an announcement shortly,” he said, adding that “the book and movie are separate deals.

“So I guess there will be two movies, or at least I know there will be one. I don’t know about Corrente’s. If I had to bet my money, I’d bet it on De Niro,” Cianci said.

Coincidentally, De Niro was once mentioned by Corrente as being on his wish list for the Cianci role in The Prince of Providence. Corrente had also negotiated with other movie stars to play Cianci, including Nicolas Cage and Russell Crowe. But for a long time the role went unfilled and some observers were beginning to wonder whether the film would ever be made. Corrente said he was aware of the doubters. “Everyone thought I was dragging my feet on this,” he said, “but I was just waiting for the right actor.”

Corrente praised Platt as “a journeyman actor that everyone knows can do what Philip Seymour Hoffman did for Capote.” (Hoffman won the best actor Academy Award in 2006 for his performance in that film.) “I feel this is Oliver’s chance to hit one out of the park,” added Corrente.

Other actors already signed for The Prince of Providence include Adam Goldberg, Ed Burns, Dermot Mulroney and Bradley Cooper, who will play characters in Cianci’s life.

The Hollywood Reporter said Robin Williams also was in talks to join the ensemble cast. Corrente said Williams had agreed to be in the film, but his participation was based on scheduling. He said Williams has signed to do a film for a major studio, but that the start date of that movie has yet to be set. “I only need him for a small window, for six days,” said Corrente, who believes Williams will be able to do his film.

Corrente said he wouldn’t be affected by the looming strike by the Screen Actors Guild against the major studios because he has a waiver that allows him to work during an actor’s strike because he does not have a distribution deal with a studio, which would have tied him to the contract between SAG and the studios.

Steven Feinberg, executive director of the Rhode Island Film & TV Office, said Corrente months ago applied for the tax credits awarded to films made in the state. He said the production would try to use as many locations as possible.

Corrente said that except for Cianci, the names of the other characters based on real people in his film have been changed. “It won’t really matter what the names of the other characters are,” he said. “When I mention the name of a real person to somebody, 90 percent of them don’t know who they are anyway. And that’s even in Rhode Island.”

The financing for the film is complete, he said, but Corrente would not identify his backers. “It’s private financing,” he said, “like all of my films. Very few local people are involved, but there are some.” Because of the nature of the film, “it’s a tad sensitive to name them.”

Corrente’s most recent film was last year’s Brooklyn Rules, about three young friends flirting with mobsters in 1970s New York. However, he said he promoted the Cianci film to investors more on the weight of Mamet’s screenplay than on his own name, “selling it as David Mamet at his best.” He said the script had elements of such previous Mamet hit films as Wag the Dog, The Untouchables and The Verdict.

He said that while “a lot of stuff” in the screenplay was drawn from Stanton’s book, “there’s also a lot that was public information, drawn from newspaper accounts.” He pointed out that “for all of the conversation about the book and some people saying it’s all riddled with lies and falsehoods, no one has ever filed litigation, because Stanton corroborated every statement.”

Corrente and Mamet have worked together closely before. In 1994, Corrente shot the screen version of Mamet’s tough-talking Obie Award-winning play American Buffalo on the streets of Pawtucket, with Dustin Hoffman starring.

This time, Corrente said some of the film will be shot at Providence City Hall.

Lynne McCormack, director of the city’s Art, Culture & Tourism office, said the city has been very cooperative with the productions that have been filmed in Providence, including the use of City Hall and Mayor David N. Cicilline’s office, “and we will be extending that same courtesy to Mr. Corrente.”

mjanuson@projo.com