NY1 has learned that Mayor Bill de Blasio's long-anticipated meeting with the U.S. Attorney's office is set to happen Friday morning at his attorney's office in Midtown.

For the past two days, the mayor has been holed up in his attorney's office for hours at a time, presumably preparing for this interview.

It comes as the U.S. attorney's office potentially wraps up a lengthy investigation into the mayor's fundraising and campaign activities.

The mayor voluntarily agreed to sit down with federal investigators and he has not requested or been offered immunity to do so. His office has said the mayor and his aides have always acted appropriately.

The mayor is also under investigation by the Manhattan District Attorney's office in connection with State Senate campaigns that he assisted in 2014.