Ghislaine Maxwell has secretly married and is refusing to reveal the name of her spouse, New York prosecutors said during her bail hearing this week.
The British former socialite, 58, is being held in a New York jail on charges of alleged sex crimes including trafficking a minor and perjury.
She has pleaded not guilty to all the charges against her.
On Tuesday, she was denied bail as she was deemed a flight risk and the shock detail of her marriage was revealed by prosecutors who claim she is hiding the extent of her wealth.
"In addition to failing to describe in any way the absence of proposed cosigners of a bond, the defendant also makes no mention whatsoever about the financial circumstances or assets of her spouse whose identity she declined to provide to Pretrial Services," Assistant US Attorney Alison Moe told Manhattan federal court Judge Alison Nathan during a video conference.
Moe added, "There's no information about who will be co-signing this bond or their assets, and no details whatsoever."
Maxwell's lawyers had asked for her to be released on a US$5 million bond and said she was at risk of contracting coronavirus in prison.
However prosecutors claimed Maxwell was an "extreme" flight risk and had claimed she bought her luxury New Hampshire home under an alias.
Judge Nathan ultimately agreed with the government, and said her presence in court could not be assured.
"The risks," she said, "are simply too great."
The identity of Maxwell's spouse is undisclosed, however she has recently been linked to Scott Borgerson, the wealthy boss of CargoMetrics. He has denied their relationship, claiming they were simply old friends.
On Tuesday, Maxwell broke down in tears in court as she was denied bail to live in a Manhattan hotel.
She was pictured in a court sketch wearing a brown T-shirt with her hair tied up in a bun.
Judge Nathan set a trial date July 12 2021, and the government proposed blocking out three weeks for the trial.
It comes after prosecutors revealed Maxwell had hidden from FBI agents during her arrest and had her mobile phone wrapped in tin foil in an attempt to conceal her location.
Attorneys for the Southern District of New York said in a court filing that agents had to breach the front door of the luxury home, Tucked Away to detain her on July 2.
"Through a window, the agents saw the defendant ignore the direction to open the door and, instead, try to flee to another room in the house, quickly shutting a door behind her," the prosecution wrote.
Maxwell faces up to 35 years in prison if convicted.