Rudy Giuliani, a leading promoter of Donald Trump’s lies about a stolen election, has been interviewed by federal investigators as part of special counsel Jack Smith’s investigation into efforts to overturn the 2020 election, his spokesman said Tuesday.

«The appearance was entirely voluntary and conducted in a professional manner,» the spokesman, Ted Goodman, said in a statement.

The nature of the questions put to Giuliani, who previously worked as a lawyer for Trump, was not immediately clear.

An attorney for Giuliani, Robert Costello, did not immediately respond to requests for comment Tuesday night. The Justice Department also did not immediately respond to NBC News’ request for comment.

CNN first reported about Giuliani’s meeting with investigators.

NBC News has previously reported that Smith aforementioned local officials in key battleground states over communications involving Trump, his campaign and a host of aides and allies who helped him in his effort to overturn the 2020 election, in an indication that Smith was investigating a scheme that involved fake voters.

Earlier this month, Nevada’s «fake electors» appeared before a federal grand jury in Washington, DC. The same grand jury subpoenaed former Trump White House official Steve Bannon in connection with the Smith investigation.

Smith, who is also overseeing the recent impeachment of Trump in a separate investigation into his handling of classified documents, has not announced any charges in the election inquiry.

In a separate investigation into possible interference in the 2020 election, Giuliani testified last year before a grand jury in Atlanta convened by Fulton County District Attorney Fani Willis, who subpoenaed Giuliani as a material witness and later told him. reported that he was a «target» of the criminal investigation.

Willis said last month that he plans to announce charging decisions in that investigation beginning in August.

Giuliani also testified before the now-defunct House committee that investigated Trump’s role in the January 6 riots and efforts to nullify the election.