2 more Trump aides testifying for Jan. 6 committee: Ex-spokeswoman, NSC member will appear Thursday

Two more aides in Donald Trump's White House are expected to testify before the House Jan. 6 committee during its public hearings, sources say -- this time an ex-spokeswoman for the former president as well as one of his previous security advisers.

Former deputy White House press secretary Sarah Matthews and Matthew Pottinger, a member of the National Security Council during the Trump administration, are slated to speak at the committee’s hearing on Thursday, sources familiar with the matter confirmed to ABC News. Both Matthews and Pottinger previously spoke behind closed doors for the panel; clips from those interviews have already been shown at prior hearings.

Their planned appearances on Thursday were previously reported by CNN.

Both Matthews and Pottinger resigned from their positions in the White House on Jan. 6, 2021, in the wake of the Capitol rioting by a pro-Trump mob.

Neither a committee spokesperson nor representatives for Matthews or Pottinger responded to ABC News.

Numerous other Trump advisers and aides have already spoken with the committee either in recorded closed-door depositions or the public sessions. Those include his daughter and son-in-law, Ivanka Trump and Jared Kushner; his White House counsel Pat Cipollone; his former Attorney General Bill Barr and more.

Committee members have said Thursday's hearing -- the eighth of the latest sessions held by the panel since June, following a year-long investigation -- will focus on the Trump White House's reaction to the insurrection as it unfolded.

"You will hear that Trump never picked up the phone that day to order his administration to help," Vice Chair Liz Cheney, R-Wyo., said last week. "This is not ambiguous. He did not call the military. The secretary of defense received no order. He did not call his attorney general. He did not talk to the Department of Homeland Security. [Vice President] Mike Pence did all of those things."

Rep. Elaine Luria, a member of the committee who will be co-leading Thursday's hearing, told "GMA 3" last week that the plan was to "go through that 187 minutes" -- the gap, as the committee describes it, between when Trump incensed his supporters at a speech near the White House on Jan. 6 and later sent public statements trying to tamp down the rioting.

Luria, a Virginia Democrat and Navy veteran who will be leading the hearing with Rep. Adam Kinzinger R-Ill., told "GMA 3" that Americans can expect the most detailed timeline of the riot.

"Mr. Kinzinger and I plan to go through that 187 minutes. What happened between the time that [former President Trump] left the stage, gave these inflammatory remarks and gave people the impression ... that he was going to himself march with this crowd to the Capitol," Luria said.

At the committee's June 16 hearing focused on the pressure campaign on then-Vice President Pence, a clip from Matthews' prior testimony was played where she described what it was like on the White House press team during the insurrection. She said that Trump's tweet attacking Pence during the riot "felt like he was pouring gasoline on the fire."

At the June 28 hearing, the committee played a brief clip of earlier testimony by Pottinger describing how that Trump tweet about Pence not having the "courage" to overturn the election triggered him to resign.

The committee played another clip from Matthews' prior testimony at the July 12 hearing where she discussed a staff meeting in the Oval Office with Trump on Jan. 5, 2021, the day before the Capitol riot. Matthews described Trump's mood as "very good" and said the crowd already gathering at the Ellipse in anticipation of Trump's speech was so loud "you could feel it shaking in the Oval."

This week's hearing is expected to be "the last one at this point," the committee chair, Mississippi Democrat Bennie Thompson, said last week. He said Monday that more hearings will be held once the committee is prepared to present its report later in the year.

Trump has denied wrongdoing and has repeatedly assailed the committee as one-sided and politically motivated.

ABC News' Lalee Ibssa, Mariam Khan and Ivan Pereira contributed to this report.