AT&T and Time Warner, facing a lawsuit by the Trump administration's Department of Justice to block the telco's $85 billion takeover of Time Warner, have extended their merger agreement until April 22, 2018.

AT&T disclosed the extension of the merger-termination date in an 8-K filing Tuesday with the SEC.

On Nov. 20, the DOJ surprised many industry observers with its lawsuit to halt AT&T's merger with Time Warner on antitrust grounds. The case may be headed toward a historic courtroom showdown.

The telco noted in the filing, "AT&T intends to vigorously contest the DOJ's allegations and is confident that the Court will reject the DOJ's challenge to the merger."

AT&T's deal for Time Warner, originally struck Oct. 22, 2016, would combine the media conglomerate's Warner Bros., Turner and HBO divisions with the telecom giant.