The jinx ... Robert Durst is set to spend the next seven years in prison. Picture: AP

US District Judge Kurt Engelhardt approved the sentence during a hearing in New Orleans.

The 72-year-old Durst had accepted the sentence as part of his guilty plea in February and was waiting for judicial approval.

Mr Engelhardt also fined Durst $US5000 and said that his sentence, once served, would be followed by three years of supervised release.

Prison bound ... New York City real estate heir Robert Durst leaves a Houston courtroom. Picture: APSource:AP

Ten years and a $US250,000 fine would have been the maximum sentence that Durst could have faced for illegally carrying a .38-calibre revolver after being convicted of a felony.

Durst still faces a separate murder charge in California.

Durst is charged in Los Angeles with killing a female friend, Susan Berman, in 2000 to keep her from talking to New York prosecutors about the disappearance of Durst’s first wife in 1982.

Dead ... Robert Durst escaped the death penalty for the murder of Morris Black. Picture: SuppliedSource:Supplied

Never found ... Robert Durst with his first wife, Kathie, whose body has never been found. Picture: HBOSource:Supplied

His lawyers have said repeatedly that he is innocent, does not know who killed Berman, and wants to prove it.

“I have been waiting to get to California for about a year so I can state my not guilty plea,” Durst told the court. “I truly, truly want to express my statement that I am not guilty in the death of Susan Berman.”

While federal guidelines recommended a sentence of between 12 and 18 months, Mr Engelhardt said the sentence was “reasonable” since it included agreements in three jurisdictions.

Under the deal, the US lawyer in the southern District of New York; the US Attorney in the southern District of Texas; and the Orleans Parish agreed not to prosecute Durst on a variety of offences.

Durst’s attorneys and prosecutors in Los Angeles have agreed that he will be in Los Angeles by mid-August.

Gave the game away ... Robert Durst basically confessed to murder in The Jinx. Picture: SuppliedSource:News Corp Australia

Assistant US Attorney Michael McMahon says it is likely he will leave Louisiana must sooner than that.

“He’ll be out of here pretty quickly,” Mr McMahon said, noting that timing and the specific prison that Durst goes to is up to the federal Bureau of Prisons.

Lawyers for Durst filed a motion on Monday to ask Mr Engelhardt to recommend that Durst serve his time at FCI Terminal Island, California, about 50 kilometres from downtown Los Angeles.

The location is near the trial venue and has medical facilities Durst needs because of his “advanced age and serious health considerations, including mobility challenges.”

High profile ... Robert Durst in a promo shot for The Jinx. Picture: SuppliedSource:Supplied

Hit doco ... The Jinx: The Life and Deaths of Robert Durst. Picture: HBOSource:Supplied

An estranged member of the wealthy New York real estate family that runs 1 World Trade Center, Durst was tracked to New Orleans in March 2015 by FBI agents worried that he was about to flee to Cuba.

He was detained at a hotel on the eve of the finale of a six-part documentary about him, and was arrested early on the morning of the show.

The Jinx described the disappearance of Kathleen Durst, the death and dismemberment of a neighbour, Morris Black, in Galveston, Texas, and Berman’s death.

At the end of the show, Durst is heard muttering, “What the hell did I do? Killed them all, of course.”