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.

Michael Cohen testified about the April 9, 2018, FBI raid on his hotel room and office as part of a federal investigation related to the Stormy Daniels matter. At the time, Cohen's apartment was flooded, so he was residing in a hotel.

"At 7 o'clock in the morning, there is a knock on the door and I look through the peephole and I see a ton of people out in the hallway. I saw a badge ... they identified themselves at the FBI," Cohen said.

Cohen told jurors that the FBI seized two phones, a series of tax books, and other records.

"I found out that simultaneously they had also raided my apartment that was under construction, my law office, and my bank that had a safety deposit box I had just opened in order to hold valuables in because I didn't want to keep them in the hotel," he testified.

"How would you describe your life being turned upside down?" prosecutor Susan Hoffinger asked.

"Concerned. Despondent. Angry,” Cohen said, describing his response to the raid.

"Were you frightened?" Hoffinger asked.

"Yes, ma'am," Cohen said.

Cohen said that he left a message for Trump after the raid, and received a phone call from Trump.

"I received a phone call from President Trump in response to me leaving a message for him to call," Cohen said. "I wanted obviously for him to know what was taking place. He said, don't worry, I am the president of the United States -- there is nothing here. Everything is going to be OK. Stay tough. You are going to be OK."

Cohen said Trump's statements at the time" reinforced my loyalty and my intention to stay in the fold." At the time, the Trump Organization was paying his legal fees.

Cohen said this was the last time he spoke to Trump.

Jurors then saw an April 21, 2018, tweet from then-President Trump that referenced the possibility Cohen might "flip" -- i.e., decide to turn on him.

Cohen said he understood those tweets as being directed "to me" -- meant to indicate, "stay in fold, stay loyal, I have you ... don't flip."

"Mr. Trump did not want me to cooperate with the government, certainly not to provide information or flip," Cohen said.