Donald Trump Jr. will testify Wednesday behind closed doors before the Republican-led Senate Intelligence Committee, Fox News has learned, as part of what the president has called an "unfair" effort to subject his son to yet another interview on Russia-related matters.

Fox News is told that the interview will likely be relatively brief. “It’s not going to go on for three hours," a source familiar with the matter said.

Trump Jr. has already provided more than two dozen hours of testimony before Congress. He previously spoke with the intelligence committee staff in 2017, when he also sat for an interview with the Senate Judiciary Committee.

The latest meeting comes after the committee's Republican chairman, North Carolina Sen. Richard Burr, subpoenaed him as part of the panel's Russia investigation. Burr received considerable blowback from some of his GOP colleagues for the move, but he told fellow senators that Trump Jr. had backed out of an interview twice, forcing the committee to act.

HOUSE VOTES TO HOLD BARR, MCGAHN IN 'CONTEMPT' AS DOJ BLASTS 'TALKING POINT,' GOP REPS FUME

Fox News reported last month that Trump Jr. was prepared to make the committee hold him in contempt and had a defiant letter drafted and ready to send -- but at the last minute, the committee reached out to resolve the dispute. The draft letter cited Trump Jr.'s 20-plus hours of testimony under oath, and the thousands of documents that he has already given to congressional committees -- as well as Special Counsel Robert Mueller's exhaustive analysis of that testimony. Mueller found no evidence Trump Jr. committed a crime.

Trump Jr. had been concerned about an open-ended time and subject commitment, sources told Fox News in May. Ultimately, the panel agreed to limit questioning to one to two hours, with narrow room for followups. A source familiar with the discussions told Fox News the panel would not agree to limit topics.

ELEVENTH HOUR HOUSE INTEL DRAMA: TRUMP JR REACHES LAST-MINUTE DEAL TO TESTIFY

Several Russia-related matters are expected to be on the agenda. Trump's former lawyer, Michael Cohen, told a House committee in February that he had briefed Trump Jr. some 10 times about a plan to build a Trump Tower in Moscow before the presidential election. Trump Jr. told the Judiciary Committee in 2017 he was only "peripherally aware" of the real estate proposal.

The panel is also interested in talking to Trump Jr. about that and other topics, including a campaign meeting in Trump Tower with a Russian lawyer that captured the interest of Special Counsel Robert Mueller. Mueller's report, released in April, examined the meeting but found insufficient evidence to charge anyone with a crime.

Trump said in May he believed that his son was being treated poorly.

"It's really a tough situation because my son spent, I guess, over 20 hours testifying about something that Mueller said was 100 percent OK and now they want him to testify again," Trump told reporters at the White House. "I don't know why. I have no idea why. But it seems very unfair to me."

Some Republicans have said Trump Jr. should not comply with the subpoena, which is believed to be the first subpoena targeting a member of the president's family.

Burr's home state colleague, Sen. Thom Tillis, R-N.C., tweeted, "It's time to move on & start focusing on issues that matter to Americans." Sen. John Cornyn of Texas, a GOP member of the panel, said he understood Trump Jr.'s frustration. Cornyn's Texas colleague, Republican Sen. Ted Cruz, said there was "no need" for the subpoena.

Senate Majority Leader Mitch McConnell, R-Ky., has defended Burr, saying "none of us tell Chairman Burr how to run his committee."

Still, McConnell made it clear that he is eager to be finished with the probe, which has gone on for more than two years.

It remains uncertain when the intelligence panel will issue a final report. Burr said last month that he hopes to be finished with the investigation by the end of the year.

Fox News' Jason Donner, John Roberts and The Associated Press contributed to this report.