Former US Special Counsel Robert Mueller has agreed to testify before Congress next month on his report into Russian interference in the 2016 presidential election.
He will testify in open session before the US House of Representatives Judiciary and Intelligence Committees on 17 July.
Mr Mueller agreed to testify after the two committees issued subpoenas yesterday.
The US House Intelligence Committee Chairman Adam Schiff announced the news on Twitter.
Robert Mueller has agreed to testify before Congress pursuant to subpoena.
— Adam Schiff (@RepAdamSchiff) June 26, 2019
Russia attacked our democracy to help Trump win. Trump welcomed and used that help. As Mueller said, that should concern every American.
And now, every American will get to hear directly from Mueller.
"Robert Mueller has agreed to testify before Congress pursuant to subpoena," he said.
"Russia attacked our democracy to help Trump win. Trump welcomed and used that help. As Mueller said, that should concern every American. And now, every American will get to hear directly from Mueller."
Judiciary committee chairman Jerry Nadler confirmed that Mr Mueller would appear "in open session."
The Mueller Report released in April outlined numerous contacts between Mr Trump's election campaign and government-linked Russians, as well as evidence that the president tried on several occasions to impede the investigation.
The Democrats have been split on whether to launch impeachment proceedings against the Republican president but - fearing that much of the country is unaware of the report's contents - have been asking major figures to testify in public on its findings.
Making his first public statement about the high-stakes probe on 29 May, Mr Mueller said longstanding Justice Department guidelines prevented him from charging Mr Trump, despite at least 10 possible acts of criminal obstruction by the president.
But not indicting Mr Trump was not equivalent to clearing him, Mr Mueller said, suggesting Congress has both the constitutional powers and the responsibility to pursue the case.
For his part, President Trump has insisted Congress cannot impeach him and claimed the Mueller report contained fabricated testimony.
While many of the candidates for the 2020 Democratic nomination are pro-impeachment, House Speaker Nancy Pelosi has argued that it would be a risky move without an "ironclad" case and bipartisan support.
If the Democrat-controlled House of Representatives were to vote on formal impeachment charges, the Republican-held Senate would decide whether to convict, which requires an unlikely two-thirds majority.
"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," Mr Nadler and Mr Schiff said in a joint statement.
Mr Mueller spent nearly two years investigating Russian election interference and possible involvement by Trump and his inner circle.
He concluded that there was not sufficient proof of a criminal conspiracy but found that Mr Trump's campaign welcomed and expected to benefit electorally from information stolen and released through Russian efforts.
