Former Georgia Lt. Gov. Geoff Duncan is at the courthouse waiting to testify before the grand jury.

Duncan had said he was originally asked to testify Tuesday, indicating his testimony was moved up.

In a tweet, journalist George Chidi said he was sitting with Duncan at the courthouse.

"I'm sitting with Geoff Duncan, waiting to go," Chidi, who was also asked to appear before the grand jury, wrote in the tweet.

Multiple witnesses have been spotted and testified before the Fulton County grand jury today, including two former state lawmakers.

Former Democratic state Sen. Jen Jordan testified today, she told local outlets as she left the courthouse, saying she testified for about 40 minutes.

Former Democratic state Rep. Bee Nguyen also testified, according to a statement.

"Today, I testified in front of the Fulton County Grand Jury," the statement said. "When I took my oath of office in 2017, I swore my allegiance to our Constitution and promised to protect and defend our State and our country. On December 2020, when Rudy Giuliani and the former President’s legal team appeared before the Georgia House of Representatives, I upheld my oath and told the truth in the face of false testimony about our elections."

"Today, I reaffirmed my allegiance to our State and country -- by exercising my patriotic duty as a U.S. citizen and telling the truth under oath," she continued. "As a former lawmaker, I respect the separation of power and the crucial role that our judicial system plays in protecting our democracy by holding everyone accountable, even powerful individuals."

Georgia election official Gabriel Sterling, who spoke exclusively with ABC News’ Jon Karl over the weekend, was also spotted in the courthouse by The Atlanta Journal-Constitution.

-ABC News' Olivia Rubin, Will Steakin, Laura Romero and Richard Elliott

Journalist George Chidi, who previously said he was asked to come before the Fulton County grand jury to testify on Tuesday, now says his testimony has been moved up and he has been asked to come in Monday.

In a post on X, formerly known as Twitter, Chidi said there was a "change of plans."

"They're moving faster than they thought," he wrote.

Chidi previously said he was present as a reporter in December 2020 at the Georgia state Capitol, where a slate of so-called "alternate electors" were allegedly meeting as part of a plan that prosecutors have said was intended to keep Joe Biden from amassing 270 electoral votes when the votes were certified on Jan. 6.

Former President Donald Trump on Monday launched a string of familiar attacks against Fulton County District Attorney Fani Willis on Monday as Willis is expected to begin presenting her election interference case to a grand jury later today.

In three all-caps posts on his social media platform Truth Social, Trump attacked Willis over her investigation, blasted media leaks, specifically urged "someone" to tell the grand jury he did not interfere in the election while continuing to make false claims that the 2020 election was stolen.

-ABC News' Will Steakin