Hutchinson described Tuesday conversations she had with Rudy Giuliani and then-White House chief of staff Mark Meadows on Jan. 2, 2021 -- four days before the attack on the U.S. Capitol.

Hutchinson said Giuliani said to her something "to the effect of 'We're going to the Capitol. It's going to be great. The president's going to be there. He's going to look powerful.'"

When Hutchinson went to Meadows' office to relay her discussion with Giuliani, Meadows told her: "There is a lot going on, Cass, I don't know, things might get real, real bad on Jan. 6."

"That evening was the first moment that I remember feeling scared and nervous for what could happen on Jan. 6," Hutchinson testified. "I had a deeper concern with what was happening with the planning aspects."

Introducing Hutchinson to the American people, Chairman Bennie Thompson asked Hutchinson to recall a typical day at the White House.

"When I moved over to the White House chief of staff's office with Mr. Meadows, when he became the fourth chief of staff, it's difficult to describe a typical day," she said.

Thompson established through a series of questions how Hutchinson's office was a five to 10-second walk from the Oval Office and that she regularly engaged with members of Congress and senior members of the Trump administration.

Vice chair Liz Cheney said Cassidy Hutchinson was in a "position to know a great deal about the happenings in the Trump White House."

"Today, you will hear Ms. Hutchinson relate certain first-hand observations about President Trump's conduct on Jan. 6," Cheney said in her opening statement. "You will also hear new information regarding the actions and statements of Mr. Trump's senior advisers that day, including his chief of staff Mark Meadows, and his White House counsel."

Cheney said information will also be released on what Trump and members of the White House knew about the potential for violence on Jan. 6.

Chair Bennie Thompson, D-Miss., convened the unexpected hearing shortly after 1 p.m. with Cassidy Hutchinson, a former top aide to Trump White House chief of staff Mark Meadows, taking her seat as members took the dais.

In brief opening remarks, he explained information that she had needed to be shared with the American people "immediately" and hailed her courage.

"In recent days, the select committee has obtained new information, dealing with what was going on in the White House on Jan. 6, and in the days prior. Specific, detailed information about what the former president and his top aides were doing and saying in those critical hours. Firsthand details of what transpired in the Office of the White House chief of staff," Thompson said.

"It hasn't always been easy to get that information, because the same people who drove the former president's pressure campaign to overturn the election are now trying to cover up the truth about January 6. But thanks to the courage of certain individuals, the truth won't be buried. The American people won't be left in the dark," he added. "Our witness today is Cassidy Hutchinson, she has embodied that courage."

Cassidy Hutchinson recalled a shocking story of Trump's anger on Jan. 6 after being told he could not go to the Capitol to meet supporters following his "Save America" rally on the Ellipse -- leading to Trump physically assaulting his security detail on the way back to the White House.

Hutchinson recalled the conversation she had back at the White House just after the rally with Bobby Engel, part of Trump's security detail, who was "sitting in the chair, looking somewhat discombobulated," and Tony Ornato.

"As the president had gotten into the vehicle with Bobby, he thought they were going out of the Capitol and when Bobby had relayed to him were not, 'You don't have the access to do it, is not secure, we're going back to the West Wing.' The president had a very strong, very angry response to that," she recalled.

"Tony described him as being irate. The president said something to the effect of, 'I'm the effing president, take me up to the Capitol now' -- to which Bobby responded, 'Sir, we have to go back to the West Wing.' The president reached up towards the front of the vehicle to grab at the steering wheel. Mr. Engel grabbed his arm, said, 'Sir, you need to take your hand off the steering wheel. We're going back to the West Wing. We're not going to the Capitol.'"

"Mr. Trump used his free hand to lunge towards Bobby Engel and when Mr. Ornato recounted the story to me, he motions towards his clavicle," she said.