Donald Trump Jr. has reached an eleventh-hour agreement to testify before the Republican-led Senate Intelligence Committee, most likely in June, Fox News has learned.

The development capped a contentious episode that began when the panel, led by Chairman Richard Burr, R-N.C., and Ranking Member Mark Warner, D-Va., subpoenaed the president's son over remarks he made while testifying before the committee in 2017.

Trump Jr. had been concerned about an open-ended time and subject commitment, Fox News is told. In addition, Fox News has learned 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.

Ultimately, the panel agreed to limit questioning to 1 to 2 hours, with narrow room for follow-ups, Fox News has learned. A source familiar with the discussions told Fox News the panel never would agree to limit topics.

TRUMP 'VERY SURPRISED' BY DON JR. SUBPOENA, SAYS SON HAS TESTIFED FOR 'HOURS AND HOURS' ALREADY

Trump Jr.'s letter of refusal – which was never sent -- cited the 20-plus hours of testimony and thousands of documents that he has already given to congressional committees, as well as his exoneration in Special Counsel Robert Mueller's report.

The committee’s demand to have Trump Jr. testify again reportedly is related to former Trump attorney Michael Cohen’s testimony earlier this year. Cohen, who reported to prison this week to begin a three-year sentence, told a House committee that he had briefed Trump Jr. approximately 10 times about a plan to build a Trump Tower in Moscow.

The committee’s demand to have Trump Jr. testify reportedly is related to the earlier testimony of former Trump attorney Michael Cohen, seen here. (AP Photo/Alex Brandon, File)

But, in 2017, Trump Jr. told the Senate Intelligence Committee he was only “peripherally aware” of the proposal.

In his draft letter to the committee, Trump Jr. pointed out that Cohen has pleaded guilty to multiple federal crimes, including lying to Congress.

The Intelligence Committee's demand rankled top Republicans, including President Trump and Senate Judiciary Committee Chairman Lindsey Graham.

"Anything based on what Michael Cohen said is worthless testimony. Michael Cohen is a worthless witness, and if I were Donald Trump Jr.'s lawyer I would tell him, 'You don't need to go back into this environment anymore, you've been there for hours and hours and hours. And nothing being alleged here changes the outcome of the Mueller investigation,'" Graham, R-S.C., said. "I would call it a day."

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Trump Jr. has testified before congressional committees multiple times as part of their Russia investigations. Trump Jr. first fell under scrutiny in the early summer of 2017, after it was revealed that he helped to organize, and then attend, a meeting with Russian lawyer Natalia Veselnitskaya in Trump Tower in New York City.

The meeting initially was billed as one where Trump Jr. and members of the Trump campaign could obtain “dirt” on Hillary Clinton for their benefit in the 2016 election. The meeting apparently did not reveal any dirt on Clinton, but Trump Jr., Trump son-in-law Jared Kushner, and former Trump campaign chairman Paul Manafort attended the June 2016 meeting. Special Counsel Robert Mueller also investigated the meeting.

Both the Moscow project and June 2016 meeting are top priorities for the committee's questioning, the source said.

Fox News' Mike Emanuel and Brooke Singman contributed to this report.