In addition to Trump Jr., former national security adviser Susan Rice will speak with lawmakers in Congress Wednesday morning, a source with direct knowledge told CNN.
Sen. Dianne Feinstein, the top Democrat on the Senate judiciary committee, told CNN her panel "will have a public hearing with Mr. Trump at an appropriate time."
She did not say when or if Trump Jr. has agreed to the hearing.
"The agreement that we had is that there will be a public hearing and, if they don't come, they'll be subpoenaed," she said.
Feinstein also clarified Trump Jr. will meet with committee staff for the interview Thursday -- not the committee. She could not comment if committee members will go. She said members can drop in, but cannot take over.
Committee Chairman Chuck Grassley declined to answer questions on Trump Jr.'s appearance.
The Washington Post was first to report
Trump's planned appearance.
The Senate intelligence committee has led the bulk of Senate inquiries into the Russian interference in the 2016 election and possible collusion with the Trump campaign. But the Senate judiciary committee has ramped up its own inquiries in recent months.
He has already provided the committee with documents. One source described Trump Jr. as being cooperative with the committee.
"We look forward to a professional and productive meeting and appreciate the opportunity to assist the Committee," his lawyer told CNN after reports surfaced.
Trump Jr.'s involvement in a Trump Tower meeting in June 2016 with a Russian lawyer who promised damaging information about Hillary Clinton has been of great interest to the committee.
Meanwhile Rice, who has come under fire from House Republicans over her handling of classified intelligence reports when serving as then-President Barack Obama's national security adviser, is meeting with the House intelligence committee Wednesday morning, a source with direct knowledge told CNN.
Rice is expected to be grilled by the GOP members on the committee, led by chairman Devin Nunes, who has accused her of "unmasking the names" of Trump associates in intelligence reports. Republicans also plan to ask her about classified leaks that have appeared in the news media.
Rice has said she has done nothing wrong and already has spoken with the Senate intelligence committee about its probe into Russian meddling in the election and any collusion with Trump associates.
"Ambassador Rice is cooperating with bipartisan Russia investigations conducted by the intelligence committees as she said she would," Erin Pelton, a spokesperson for Rice, told CNN in June
Trump Jr. had planned to also meet with the Senate intelligence committee, but the committee's chairman and top Democrat have said that they'd like to talk to other attendees of the June 2016 meeting before meeting with Trump Jr.
Sen. Mark Warner, the committee's top Democrat, told CNN's Erin Burnett their panel is not wedded to meeting with Trump Jr. this month.
"We're wedded to making sure that — now we may not get everyone who was in the room cause some are Russian citizens but many of them are American citizens so we're working through that right now," Warner said on Erin Burnett's OutFront on Wednesday.
This story has been updated.