Hannity's denial fatally undermined any credible claim by Cohen that their communications were protected from disclosure by the attorney client privilege. One was obviously Trump.
Stephen Ryan, a lawyer for Mr Cohen, drew gasps and laughter from the public gallery when he named Mr Hannity as the client.
Cohen previously disclosed that in the course of the past year he had represented three clients. The Wall Street Journal reported last week that Cohen also negotiated a deal in 2017 to pay $1.6 million to a woman who said Broidy impregnated her. Wood, though, demanded the name. "That's not enough. I order you to disclose the client now", the judge said. They tried to enter the packed courtroom and were initially turned away due to the crowd, before space was found.
It's not the first time Hannity and Trump have shared a lawyer, either.
"I assumed those conversations were confidential, but to be absolutely clear they never involved any matter between me and a third party", he said.
Hannity, who said Monday that he had eight lawyers representing him in various matters, revealed last summer on his radio show that he had hired Trump attorney Jay Sekulow. I never paid Michael Cohen for legal fees. "By the way, I'm thinking of hiring Michael Cohen as my lawyer", Kimmel joked.
After his identity was revealed, Hannity said on his syndicated radio show, and again later on his Fox News program, that he had "occasional, brief discussions" with Cohen in which he sought out Cohen's "input and perspective".
The longtime Fox host said on Twitter that the small discussions centered "almost exclusively on real estate", though Hannity has come into the headlines in recent years in ways that could use a lawyer's advice.
The special counsel's office didn't conduct the raids of Cohen's office and home.
Monday's hearing began with an appearance by adult-film actress Stephanie Clifford, better known as Stormy Daniels.
Daniels sat with her lawyer, Michael Avenatti, who told reporters they were there to help ensure protection for the integrity of the seized documents, some of which they believe pertain to the Daniels agreement.
The hearing came after an Federal Bureau of Investigation raid on Mr Cohen a week ago, in which documents relating to a clandestine payment to adult film star Stormy Daniels were reportedly seized.
Lawyers for Cohen filed papers Monday saying investigators "took everything" during the raids, including more than a dozen electronic devices.
"The hearing is taking place in federal court in Manhattan".
Prosecutors say they are investigating Cohen's personal business dealings.
Allowing Cohen and Trump to review the materials before prosecutors can look at them would be a significant defeat for the government.
At the end of the show, Hannity finally got around to elaborating on his relationship with Cohen, but the segment mainly consisted of him mocking the mainstream media for its coverage of Cohen, who he now describes as "me and President Trump's personal attorney".
The searching of any attorney's office by the government is highly unusual and typically triggers the appointment of a "taint team" to check seized material for attorney-client privilege. I have many (too many!) lawyers and they are probably wondering when their offices, and even homes, are going to be raided with everything, including their phones and computers, taken.