The courtroom in the Manhattan Criminal Courthouse is packed with reporters and security ahead of Michael Cohen's testimony.

Approximately 70 reporters are crammed into the gallery of the courtroom, seated on wooden benches that seat six per row. Five members of the public are seated in the back of the gallery behind the prosecution counsel table and jury box, and five court officers are scattered throughout the courtroom.

On the right side of the courtroom, earlier witnesses Jaden Jarmel-Schneider and Georgia Longstreet are seated near computer monitors. Both work as paralegals for the Manhattan district attorney's office and testified as part of the prosecution's case.

Jarmel-Schneider introduced phone records and a summary exhibit about the falsified documents into evidence, while Longstreet introduced Trump's social media posts into evidence.

Several members of the public waited overnight to secure a spot in the courtroom for Michael Cohen's testimony, traveling from as far as Los Angeles for the momentous day in court.

Michael Powers told ABC News that he joined the line at 2:30 p.m. yesterday to secure his spot in court, though he enlisted the help of professional line sitters to hold the spot overnight. He rejoined the line at 5:00 a.m.

"It's history in the making," Powers said. "This isn't gonna happen very often."

Powers said he prioritized seeing Michael Cohen's testimony due to its importance to the prosecution's case.

"I find him credible" Powers said. "He's lied in the past, but he lied for Donald Trump in my opinion, so I think he'll be a good witness."

Other members of the public waited overnight without the use of line sitters, including Chris Sagastizabal, who joined the line at 6:45 p.m. on Sunday with two friends.

"I changed my work schedule," Sagastizabal said.

Five members in the public have been seated in the courtroom this morning, with several others seated in a nearby overflow room.

Michael Cohen has arrived at the lower Manhattan courthouse ahead of today's expected testimony.

He did not speak to reporters on his way in.

Proceedings are scheduled to get underway at 9:30 a.m. ET.

Michael Cohen, who for nearly a decade was Donald Trump's trusted adviser, personal attorney, and self-described "attack dog with a law license," is scheduled to take the stand this morning as the prosecution's star witness in Trump's criminal hush money trial.

According to prosecutors, Cohen was in the room in when Trump and former National Enquirer publisher David Pecker agreed to a catch-and-kill scheme to hide negative information about Trump from 2016 voters, and Cohen himself made a $130,000 payment to Stormy Daniels to buy her silence about an alleged 2006 sexual encounter with Trump. The former president, who has denied the encounter took place, is on trial for allegedly falsifying business records related to his company's reimbursement to Cohen in 2017.

But Cohen's value to the prosecution's case could be endangered by the disbarred lawyer's credibility issues. Cohen pleaded guilty in 2018 to tax evasion, campaign finance allegations, and lying to Congress in what Cohen says was an effort to protect Trump. The former president's lawyers have also argued that Cohen perjured himself again when he testified at Trump's civil fraud trial last year, and accuse Cohen of making his livelihood off books and podcasts that antagonize Trump.

Cohen is the final key witness in the prosecution's case, after which the defense will present its case.

Jurors saw the finalized nondisclosure agreement between Trump and Stormy Daniels, guaranteeing Daniels $130,000 for her silence.

Cohen signed the document on behalf of Essential Consultants.

The agreement used pseudonyms for Trump and Daniels -- Trump's being David Dennison and Daniels' being Peggy Peterson.

"The purpose of it was to ensure his name didn't appear anywhere, as he is a candidate for the presidency of the United States of America," Daniels said.

Donald Trump's name briefly appeared on a side letter agreement to confirm that he was the David Dennison mentioned in the contract.

Both Davidson and Cohen were permitted to have a copy of the side letter agreement.

Jurors then saw a phone record showing a five-minute phone call between Cohen and Trump on Oct. 28, 2016.

Cohen said he told Trump that "this matter was now completely under control and locked down pursuant to the nondisclosure agreement."