Acting Attorney General Matt Whitaker caved to Democratic demands and will show up voluntarily before the House Judiciary Committee on Friday morning after a tumultuous day of doubts on whether or not he would testify.

'CONFIRMED: Acting Attorney General Whitaker will appear tomorrow morning at 9:30am,' Rep. Jerry Nader, the Democratic chairman of the panel, tweeted Thursday evening.

The Justice Department claimed Democrats agreed to Whitaker's demanded they would not wield a subpoena against him.

'The chairman has made the commitment that we requested, and agreed that, if Mr. Whitaker voluntarily appears at tomorrow's hearing, the Committee will not issue a subpoena on or before February 8,' Justice Department spokesperson Kerri Kupec said in a statement to CNN. 'In light of that commitment, Acting Attorney General Whitaker looks forward to voluntarily appearing at tomorrow's hearing and discussing the great work of the Department of Justice.'

Acting Attorney General Matt Whitaker will show up voluntarily for his Friday morning appearance before Congress

House Judiciary panel chair Jerry Nadler had advised Whitaker to show up

'CONFIRMED: Acting Attorney General Whitaker will appear tomorrow morning at 9:30am,' Rep. Jerry Nader, the Democratic chairman of the panel, tweeted

Earlier Thursday Whitaker wrote House Judiciary Chairman Jerry Nadler and asked for a reassurance that Democrats on his panel would not use a subpoena they pre-emptively authorized in case he avoids answering their questions.

Nadler slammed back at his demand, writing that the acting attorney general had no reason to worry if he's 'prepared to respond to questions' and ended with a cheery: 'I look forward to your testimony tomorrow.'

Whitaker had given Democrats a 6 p.m. deadline to respond in their escalating conflict.

Nadler wrote back late Thursday afternoon: 'If you appear before the Committee tomorrow morning and if you are prepared to respond to questions from our Members, then I assure you that there will be no need for the Committee to issue a subpoena on or before February 8. To the extent that you believe you are unable to fully respond to any specific question, we are prepared to handle your concerns on a case-by-case basis, both during and after tomorrow's hearing.'

He concluded with: 'Thank you, and I look forward to your testimony tomorrow.'

The House Judiciary Committee on Thursday voted to authorize the subpoena ahead of his testimony.

Democrats want to ask Whitaker about his conversations with President Trump and Whitaker's decision not to recuse himself from special counsel Robert Mueller's Russia probe. They are worried he may not answer.

Asked whether Whitaker wouldn't testify due to a subpoena threat, President Donald Trump replied, 'That I don't know.'

'He's an outstanding person. I would say if he did testify he'd do very well,' the president told reporters Thursday in the Oval Office.

The conflict began Thursday morning when the Justice Department sent a letter to the committee asking for reassurances before the acting attorney general met with them.

'I remain willing to appear to testify tomorrow, provided that the chairman assures me that the committee will not issue a subpoena today or tomorrow, and that the committee will engage in good faith negotiations before taking such a step down the road,' Whitaker said in a statement.

He added: 'Political theater is not the purpose of an oversight hearing, and I will not allow that to be the case.'

Nadler said during Thursday's authorization vote that he hoped not to have to use the subpoena but wanted to be prepared in case it was needed.

'I hope not to have to use the subpoena,' he said. 'Unfortunately a series of troubling events over the last few months suggest that we should be prepared.'

Democrats worry Whitmaker may try to evade some of their questions and wanted a subpoena on hand to use if that is the case.

'If Mr. Whitaker appears in the hearing room, as scheduled, and if he provides direct answers to our questions, then I have no intention of ever issuing this subpoena,' Nadler said Thursday.

The resolution to authorized the subpoena passed on a party-line vote, 23 to 13.

In a letter to Nadler, the Justice Department outlined the questions that Whitaker is prepared to answer.

Friday's hearing would likely be Acting Attorney General Matt Whitaker's last appearance before Congress

House Judiciary Committee members gather during a debate to subpoena Acting Attorney General Matthew Whitaker on Thursday

'The Acting Attorney General will testify that at no time did the White House ask for, or did the Acting Attorney General provide, any promises or commitments concerning the Special Counsel's investigation,' Assistant Attorney General Stephen Boyd wrote in a letter obtained by CNN. 'With respect to the Special Counsel investigation, the Department has complied with the Special Counsel regulations, and the Acting Attorney General will make clear that there has been no change in how the Department has worked with the Special Counsel's office.'

Nadler argued the subpoena was necessary because Whitaker would not tell the committee whether or not he planned to invoke executive privilege.

Friday's hearing would likely be Whitaker's last appearance before Congress.

On Thursday, the Senate Judiciary Committee voted to advance William Barr's nomination as attorney general to the Senate floor, setting up a vote for next week.