Sopranos creator David Chase is headed to federal court in New Jersey to defend his role in creating the hit HBO mob drama.

Jury selection begins in Trenton on Wednesday in the case of a former New Jersey municipal court judge who claims his ideas helped Chase come up with the show's plot.

Robert Baer, also a former assistant prosecutor in Union and Hudson counties, sued Chase in 2002, claiming he suggested a TV show about organized crime in New Jersey and gave Chase a crash course on the north Jersey mob.

In court documents, Chase countered that Baer is "self-delusional." He is expected to testify at the trial. 

U.S. District Judge Joel A. Pisano dismissed Baer's lawsuit twice, but those rulings have been overturned.

The legal dispute centres on Baer's role in developing the show in 1995, years before The Sopranos became a cable sensation.

"He proposed the idea about doing the show about the north Jersey mafia," said his attorney, Harley D. Breite. "He's looking to be compensated for the value of what he did, the services and assistance he provided to Mr. Chase."

The lawsuit doesn't specify a dollar amount.

Baer first met Chase for lunch at a California restaurant. They were introduced through a mutual friend.

"After the lunch ended, Chase took Baer's phone number and reached out to him and asked for his help in doing this project," Breite said.

Baer says that, months later, he gave Chase a tour and tutorial about the Jersey mob over three days, arranging meetings with police detectives and other experts who could provide background.

Breite said Baer contributed ideas that became part of the show, including a pork store in Elizabeth that would become the mobster's favourite hangout and a Jewish character that had ties to the mob.

The lawsuit claims Chase later made phone calls to Baer at his north Jersey home to ask questions about the mafia in the state. Chase sent Baer a draft of the proposed first episode, according to the lawsuit. Baer responded 14 months later but "didn't make a single suggestion for improvement of my script," Chase said in a court filing.

Breite said Baer attempted several times to contact Chase after the show was sold to HBO, but he didn't respond. 

In a 2002 court filing, Chase called Baer's claims "grossly distorted, petulant and self-aggrandizing" and that Baer provided a "modest service," arranging to introduce him to individuals who were experienced in certain facets of organized crime.

Chase also said practically all of the information provided to him during his visit with Baer exists in the public domain and wasn't original.

In a court filing, Chase was "keenly aware of a 'mob presence' in New Jersey" because he grew up in the Garden State. 

A spokeswoman for Chase declined to comment on specifics of the case except to express confidence he would prevail in court.