(CNN) Robert Mueller will testify before Congress on July 17 after House Democrats issued a subpoena for his appearance, a move that paves the way for a reluctant special counsel to answer questions publicly for the first time about his 22-month investigation into President Donald Trump.

The House Judiciary and Intelligence Committees announced Tuesday that Mueller had agreed to testify after they issued subpoenas for his testimony, and Mueller would appear in public before the two panels next month.

"Americans have demanded to hear directly from the Special Counsel so they can understand what he and his team examined, uncovered, and determined about Russia's attack on our democracy, the Trump campaign's acceptance and use of that help, and President Trump and his associates' obstruction of the investigation into that attack," House Judiciary Chairman Jerry Nadler and House Intelligence Chairman Adam Schiff said in a joint statement.

Mueller's testimony is poised to be the most-anticipated congressional hearing in years, and represents a huge moment for House Democrats who have wrestled with whether to dive into a politically divisive impeachment process following the Mueller investigation and White House stonewalling of congressional probes.

Trump responded to the news on Twitter Tuesday with a familiar two-word refrain: "Presidential Harassment!"

The subpoenas to Mueller come after weeks of negotiations between Democrats, the special counsel's team and the Justice Department. Democrats are proceeding with subpoenas to Mueller after he spoke publicly last month and said he did not wish to testify publicly about the investigation, and that his testimony would not go beyond what was written in the special counsel's 448-page report

"He was and is deeply reluctant to come testify, but nonetheless he has agreed to respect the subpoena," Schiff told CNN on Tuesday evening.

Schiff said that the committees would be questioning Mueller separately the same day, and that his committee would question Mueller's staff in closed session following the public hearing so they can discuss the counterintelligence portions of the investigation.

In a letter to Mueller, the Democratic chairmen said that they understood Mueller's concerns about ongoing investigations referred by the special counsel, but still felt it was necessary for him to testify.

"We will work with you to address legitimate concerns about preserving the integrity of your work, but we expect that you will appear before our Committees as scheduled," Nadler and Schiff wrote.

Democrats have been talking about bringing Mueller in to testify since his investigation wrapped in March, and their decision to issue subpoenas comes more than a month after the initial date that Nadler had floated for Mueller to appear.

Since then, Democrats have continued to negotiate with Mueller, holding out hope he would agree to testify voluntarily. While Mueller stated he did not wish appear before Congress, Democrats — and some Republicans — have said they still believe Mueller should testify. Democrats have argued that the American people can hear directly from the special counsel in a public setting, and lawmakers in both parties have said they want to ask him about some of the decisions made during the investigation.

For Republicans, Mueller's appearance offers them a chance to press the special counsel about their concerns regarding the origins of the counterintelligence investigation into the President's team, and pressure Democrats to drop their own investigations into the President.

"I hope the special counsel's testimony marks an end to the political gamesmanship that Judiciary Democrats have pursued at great cost to taxpayers," said Rep. Doug Collins of Georgia, the top Republican on the Judiciary Committee. "May this testimony bring to House Democrats the closure that the rest of America has enjoyed for months, and may it enable them to return to the business of legislating."

Mueller's report was written in two parts: a volume on Russian election meddling and one on obstruction.

In the first volume, the special counsel did not establish a criminal conspiracy between the Trump campaign and the Russian government, but it did detail numerous contacts between Russians and members of Trump's team that Democrats charge are troubling, even if they aren't criminal. In the second volume, Mueller documented nearly a dozen episodes of possible obstruction of justice. The special counsel wrote that DOJ guidelines did not allow a sitting president to be indicted, and that the investigation could not exonerate Trump.

Mueller's public statement last month noted specifically that his investigation did not exonerate Trump, and he also pointed out that "the Constitution requires a process other than the criminal justice system to formally accuse a sitting president of wrongdoing." The statement, Mueller's only public comments since he was appointed special counsel in May 2017, sparked a wave of House Democrats to call for the opening of an impeachment inquiry.

Their numbers have grown amid White House stonewalling of testimony and documents to congressional investigations, and now more than 75 have come out in favor of opening an impeachment inquiry.

But House Speaker Nancy Pelosi has continued to resist the move, arguing that Democrats are winning their court fights with the Trump administration and impeachment should only be pursued if the public is on board.

Schiff and Nadler have both publicly refrained from calling for the opening of an impeachment inquiry. Behind the scenes, Nadler has lobbied Pelosi to do so, while Schiff has argued against it.

"This will be an opportunity to amplify the message of the report, and then, you know, we'll let the chips fall where they may," said Rep. Jamie Raskin, a Maryland Democrat on the Judiciary Committee who has pushed for opening an impeachment inquiry.

When he spoke last month, Mueller argued that he did not need to testify because he would not go beyond what was written the report. "The report is my testimony," Mueller said.

But lawmakers in both parties have said they believe Mueller can nevertheless answer their questions, and Democrats have specifically pointed to Attorney General William Barr's statements on the investigation, which they felt misrepresented Mueller's work.

"There's been a campaign of misrepresentation from Attorney General Barr, who misrepresented what was in the report; by the President — the President saying they found no collusion, that's not true," Nadler told CNN. "So it's important that he answer a lot of specific questions."

Nadler said he wanted to ask Mueller, for instance, about the letter he wrote to Barr questioning his four-page summary of the investigation

Schiff said Democrats on his committee have questions about the counterintelligence portion of the investigation and the prosecutorial decisions made.

"There's no limitation on confining his testimony to the four corners of the report," Schiff said. "That may be his desire, but Congress has questions that go beyond the report, and we have seen with the attorney general, he is more than willing to make statements that go well beyond anything in the Mueller report."

Republicans, meanwhile, are likely to focus on the origins of the investigation — which the GOP-led Congress investigated last year — as well as the removal of former FBI agent Peter Strzok from his team after Strzok exchanged anti-Trump text messages with former FBI lawyer Lisa Page.

"I've got a lot of questions about how Robert Mueller's team was assembled," said Rep. Matt Gaetz, a Florida Republican on the Judiciary Committee. "I think we are also interested in figuring out when he ultimately decided there wasn't going to be a charge for criminal conspiracy."

This story has been updated with additional developments Tuesday.