Fired FBI Director James Comey is prepared to be interviewed by Special Counsel Robert Mueller in connection with the investigation into Russian interference in the 2016 presidential campaign, a source close to Comey tells Fox News.

The source added that Comey is also prepared to testify before Congress, a move contingent on him speaking to Mueller.

"I wouldn’t say Jim is excited about it,” the source said of Comey's potential testimony. "But he’s ready."

On Monday, House oversight committee chairman Jason Chaffetz, R-Utah, tweeted that he had postponed a planned Wednesday hearing at which Comey would have testified.

President Trump fired Comey as FBI Director on May 9. The White House initially circulated a memo from Deputy Attorney General Rod Rosenstein criticizing Comey's conduct during the investigation into former Secretary of State Hillary Clinton's private email server. However, Trump told NBC News in an interview two days later that "when I decided to just [fire Comey], I said to myself, I said you know, this Russia thing with Trump and Russia is a made-up story."

The following week, Comey associates revealed that the then-FBI Director had written a memo detailing a Feb. 14 conversation with the president in which Trump asked him to close down the bureau's investigation into former national security adviser Michael Flynn.

Mueller, Comey's predecessor as FBI director, was appointed May 17 by Rosenstein as special counsel "to ensure a full and thorough investigation of the Russian government’s efforts to interfere in the 2016 presidential election."

Senior Justice Department officials say Mueller will have all the powers of a U.S. Attorney, including the ability to empanel a Grand Jury.

In an ironic twist, current and former Trump administration and campaign officials are reportedly being represented by the WilmerHale law firm, where Mueller worked as a partner prior to his appointment as special counsel. Mueller resigned his position at the firm following his appointment.