Cohen was the target of an FBI raid last week, and the person who paid Daniels $130,000 on the eve of the 2016 presidential election.
Documents about that payoff, which Daniels has said was in exchange for her silence about an affair she had with Trump in 2006, were among the items seized from Cohen by the FBI.
Cohen is expected to make his first appearance at the hearing in U.S. District Court in New York, where his presence has been ordered by a judge considering hisrequest on how to handle materials seized in the FBI raid.
During an appearance on CNN's "State of the Union," Daniels' lawyer Michael Avenatti, revealed she would be there to watch Cohen.
"I think Monday afternoon could prove to be very interesting," Avenatti said.
Asked by CNN if Daniels' presence was meant to provoke Cohen, Avenatti said, "No, not at all."
"It's intending to send a message that this is a very, very serious matter for her, and she wants to make sure that the American people know that she's behind efforts to bring to light as much information and documents as possible," Avenatti said.
"She wants to ensure that she is heard."
"This has nothing to do with getting into his head at all," the lawyer said.
But Avenatti, who was at the initial court hearing Friday related to Cohen's request, in a subsequent tweet on Sunday morning referenced a scene from "The Godfather II." In that particular part of the movie, a Mafia turncoat recants his testimony after mob boss Michael Corleone brings the informant's own brother with him to watch that testimony.
The White House has denied Trump had sex with Daniels, whose real name is Stephanie Clifford.
In addition to files about Daniels, FBI agents reportedly sought information about a payoff to another woman who said she had an affair with Trump when they seized materials seized in the New York City raid on Cohen's office, home, hotel room and electronic devices last Monday.
The raid, which also sought filed related to Cohen's business interests, enraged Trump, who claims it violated attorney-client privilege he has with Cohen.
Prosecutors conducting a criminal investigation of Cohen have said they have been probing Cohen for months, and that a grand jury has been reviewing evidence. Prosecutors also said that covert surveillance was conducted on several email accounts of his before Monday's raid.
Prosecutors said they were worried that if the FBI did not conduct those raids that evidence related to the case could end up being destroyed without a trace.
The United States Attorney's Office for the Southern District of New York, which is handling the case, plans to avoid violating the attorney-client privilege by using a special process to handle materials seize from Cohen.
That process calls for a so-called filter team made up of prosecutors not associated with the case would review the materials, determine which ones are protected by privilege, and hand over the remaining materials to the prosecutors in the case. The U.S. Attorney's office has noted that that process has been used in the past in criminal cases against lawyers.
But Cohen in a court filing late Thursday night requested a different process, one that prosecutors say would be unprecedented. Cohen wants his own lawyers to review the material, determine what information is privileged, and then turn over the unprivileged evidence to prosecutors.
Failing that, Cohen is asking that a so-called special master judge be named to review the materials, to avoid privileged documents from being seen by the prosecution.