Washington (CNN) The congressional testimony of President Donald Trump's ex-lawyer Michael Cohen is already set to be one of the most highly anticipated moments of the new Democratic-controlled House, but those expecting significant public insights into the Russia investigation could be disappointed.

Cohen is not expected to answer questions about any topics related to that investigation when he appears before the House Oversight Committee next month because special counsel Robert Mueller's investigation is ongoing. He consulted with the special counsel before agreeing to appear at the hearing, two sources told CNN.

That doesn't mean Cohen's testimony won't have dramatic reveals.

Cohen is prepared to discuss topics related to hush money payments and aspects of the Trump Organization, including the roles of the President and his children, according to a source familiar with the matter.

Cohen is willing to detail -- if asked -- then-candidate Trump's role in directing payments to two women who have claimed they had affairs with Trump and how his election played a role in that, according to the source. Trump has denied affairs with the women. Cohen may also talk about how he thinks his incarceration for tax evasion is unfair, the source said.

Cohen's testimony has raised questions about what he can say publicly given that the Mueller probe continues.

House Oversight Chairman Elijah Cummings said his staff has been consulting with Mueller about Cohen's appearance and will continue to do so ahead of his February 7 hearing.

"We will not interfere with the Mueller investigation," the Maryland Democrat said Friday. "Those discussions (with the special counsel) may very well go on until the day before ... because Mueller is ongoing."

Cohen is appearing before Congress next month after he pleaded guilty in December to multiple charges and was sentenced to three years in prison. Cohen pleaded guilty to campaign finance crimes that included payments during the campaign to silence the women alleging affairs -- crimes that prosecutors say Trump directed Cohen to commit. Trump has denied he directed Cohen to make the payments.

Cohen also pleaded guilty to lying to Congress about how long the proposed Trump Tower Moscow project discussions extended into the 2016 campaign when he testified before the congressional intelligence committees in 2017.

It's not yet clear what specific topics might be off limits. Cummings declined to say, for example, whether Cohen would be allowed to talk about Trump Tower Moscow.

Asked if hush money payments would be part of the hearing, Cummings said his committee was "in search of the truth."

"The American people will have an opportunity to hear from him, Mr. Cohen," Cummings said. "And their representatives, that is representatives on the Republican side and the Democratic side, will have an opportunity to ask him questions, and I think the American people would see that it did matter, their votes did matter, and we opened it up for transparency."

One Democratic member of the panel cautioned fellow Democrats not to give Republicans what they want -- turning the hearing into a "circus" by asking intimate questions about Trump's alleged affairs.

Cohen's testimony before the oversight panel is public, so he won't talk about the Russia investigation there, but he could have those discussions with Congress behind closed doors before other panels. Both the House and Senate intelligence panels are seeking to bring back Cohen before he reports to prison in March.

"It's my understanding that he doesn't intend to address the Russia investigation in his open testimony. He is going to need to answer questions about it and we're in contact with the attorney," House Intelligence Chairman Adam Schiff of California told CNN on Thursday. "We hope that he will come in voluntarily to testify before the Intel Committee in closed session."

According to a source familiar with the matter, Cohen has not yet committed to testify to either of the intelligence committees.

Even if Mueller does not want Cohen answering questions that touch on the Russia investigation, that doesn't mean they won't be asked at his public hearing. Ohio Rep. Jim Jordan, the top Republican on the oversight committee, didn't rule out pressing Cohen on questions related to any topic.

"It seems to me if he comes in there, we should be able to ask him about whatever we want to ask him about," Jordan said Friday.

On Friday, Jordan sent a letter to Cummings asking him to include Republican staffers in discussions with Cohen's lawyers and Mueller's team about Cohen's testimony. Jordan also asked Cummings to seek a host of records from the Justice Department and the FBI about Cohen, including notes of their interviews with Cohen, investigative reports and cooperation agreements.

"I hope you will work with me and the minority members to avoid an unproductive and chaotic hearing," Jordan wrote. "If you are going to provide a platform for this convicted felon and perjurer, we ought to ensure we have the necessary information to prepare to question him."

Jordan was frequently frustrated when Republicans were investigating FBI and Justice Department conduct in 2016 that his questions about the origins of the Russia investigation and a foreign intelligence surveillance warrant were rebuffed by DOJ lawyers.

"I've tried to ask all kinds of questions in every one of these depositions and I've had like 15 lawyers sitting in there telling the witness they couldn't answer the question," he said.

"For a year and a half (the Democrats) said we don't want to do anything to disrupt the Mueller investigation, but we're going to bring in their star witness before the Mueller investigation is done."

Rep. Mark Meadows of North Carolina, the House Freedom Caucus chairman and a close GOP ally of Trump on the oversight panel, hinted at the acrimony Cohen should expect from the Republican questioners.

"I think it's strange that the very first big hearing, the witness is a convicted felon who's going to prison because he lied to Congress," Meadows said.

Cohen could use his willingness to testify as a way to appeal for a more reduced sentence, though there is no agreement with prosecutors to consider that. He is due to start his three-year sentence on March 6.