Comey will speak to an open hearing of the Senate Intelligence Committee followed by a closed session, the committee announced Thursday. The hearing is part of the panel's probe into alleged Russian meddling in the 2016 election and any possible ties between the Trump campaign and the Kremlin.
Comey was abruptly fired last month while overseeing the FBI's own investigation of alleged Russian interference.
The former FBI chief will certainly be asked about his reported conversations with Trump and any efforts the president made to interfere with the probe. Robert Mueller, who was FBI director before Comey, is now overseeing the probe as a special counsel.
It is not yet clear how much Comey will say about his conversations with Trump or an alleged memo in which Comey reportedly says the president asked him to back off the investigation into ex-national security advisor Michael Flynn.
The White House has given shifting explanations about Trump's motives for firing Comey. The administration initially said Trump acted on the Justice Department's recommendation, though Trump himself later said he would have fired Comey "regardless" and was thinking of the "Russia thing" when he decided to do so.
In an Oval Office meeting with Russian diplomats last month the day after he fired Comey, Trump also reportedly called the former FBI chief a "nut job" and said firing him relieved "great pressure," according to The New York Times.
Trump and the White House have denied any collusion with Russia related to the 2016 election.
People close to Comey say he is eager to speak in public, according to NBC News. He met with Mueller, who cleared him to testify.
It is not clear what Mueller told Comey he could say publicly. Some legal experts have said that, if Mueller is investigating possible obstruction of justice, he may not want Comey to speak in the open about his conversations with Trump, NBC reported.
Multiple reports have indicated that Comey was concerned that Trump did not respect the FBI's independence.
The White House did not immediately respond to a request for comment on this article.