Former Trump campaign aide Sam Nunberg, left, arrives at the U.S. District Courthouse in Washington to appear before a grand jury on March 9. Nunberg had insisted in interviews earlier in the week that he intended to defy a subpoena issued by special counsel Robert S. Mueller III's office, which is investigating Russian interference efforts in the 2016 presidential election. (J. Scott Applewhite/AP)

Sam Nunberg, a former Trump political aide who has met with investigators for the special counsel and was long close to Trump loyalist Roger Stone, will meet with the Senate Intelligence Committee in January as part of its continuing investigation into Russian interference in the 2016 presidential election.

Nunberg confirmed his pending meeting in an interview Tuesday with The Washington Post, saying, “I’m happy to cooperate and appear” for what is likely to be a closed session with committee staffers.

A person familiar with the committee who was not authorized to speak publicly said that Nunberg has agreed to meet with the committee in January and that the committee has asked him to refrain from speaking to reporters.

Spokesmen for both the Republican and Democratic staffs on the committee declined to comment.

Nunberg’s visit is the latest sign that the Senate Intelligence Committee’s investigation is going to carry into the new year. The committee is led by Chairman Richard Burr (R-N.C.) and ranking Democrat Mark R. Warner (D-Va.) and has largely been a bipartisan operation since its inception in comparison to the Russia investigation in the House, which has been marked by division.

Burr told Bloomberg News last month that private interviews with figures such as Nunberg are to be expected. “I don’t see the need for public hearings,” he said. “I don’t see that happening.”

Nunberg said he was uncertain about the topics of the discussion but speculated that he would be asked “about Stone, about all of my interactions with him, and about the Trump campaign,” along with possible questions about former Trump attorney Michael Cohen, whom Nunberg has known for years and who is cooperating with special counsel Robert S. Mueller III’s investigation.

Mueller and Senate investigators have been probing Stone’s knowledge of WikiLeaks, the anti-secrecy group that released hacked Democratic emails during the 2016 presidential race. Stone said Sunday on ABC News’s “This Week” that he had “no contact with [Julian] Assange,” the founder of the group.

Cohen pleaded guilty last week to lying to Congress about an ultimately unsuccessful effort to build a Trump building in Russia. He is expected to be sentenced Dec. 12.

Nunberg said he was first invited to meet with the Senate Intelligence Committee in May and was asked to preserve documents that could be relevant to the committee’s probe. He shared that invitation with The Post on Tuesday and said talks between his lawyer and the committee have been ongoing in recent weeks.

Nunberg last appeared as a player in the orbit of the Russia probe when he testified before the special counsel’s grand jury in March, after initially threatening to defy a subpoena and launching a media tour in which he railed against Mueller.

“Let him arrest me,” he told The Post at the time, before relenting and testifying.

Nunberg, while little known in Republican politics for years, was a fixture in Trump’s circle ahead of the start of his campaign, guiding Trump’s message and serving as an adviser as Trump built relationships within the GOP, working at times with Cohen at Trump Tower in New York.

Nunberg also considered himself to be a protege of Stone — a veteran GOP strategist — and kept in touch with him throughout 2016, even after both men left the campaign and clashed with Trump.

On Monday, Trump sparked controversy with several tweets related to Mueller’s investigation of possible coordination between his 2016 campaign and Russia.

In one, Trump advocated that Cohen be given prison time. In another, Trump praised Stone for not agreeing to testify against him. The tweets prompted charges of witness tampering from several high-profile lawyers.

John Wagner contributed to this report.