Hope Hicks, former White House communications director, and her legal team exit as Hicks participated in a closed-door interview with the House Judiciary Committee on June 19, 2019. Photo: Sarah Silbiger/Bloomberg

The lawyer for Summer Zervos, the former contestant on "The Apprentice" suing President Donald Trump for defamation, late last year served a subpoena to former White House communications director Hope Hicks for a deposition in the private civil suit.

The subpoena, issued through D.C. Superior Court on Dec. 17 and signed by Zervos' attorney Beth Wilkinson of Wilkinson Walsh, requested Hicks's appearance at a Jan. 23 deposition at Wilkinson's law firm in Washington, D.C. But all proceedings in the private suit were halted in early January, when the Manhattan Supreme Court paved the way for the state's highest court to review their ruling letting the case advance.

News this week that Hicks is returning to work at the White House raises new questions about whether she would appear for the deposition, if the case becomes active again.

If the New York court rules in favor of the lawsuit and the subpoena is back in play, it appears that Hicks could become the first sitting White House official called to testify in a private civil suit against Trump.

She previously complied with a House Judiciary Committee subpoena for her testimony after she first left the White House, but declined to answer questions about her time at the White House or during the Trump transition.

Wilkinson did not immediately return a request for comment. Robert Trout, Hicks' attorney with Trout Cacheris & Solomon declined to comment.

Lawyers with Kasowitz Benson Torres, who are representing Trump in the lawsuit, did not immediately return a request for comment. A White House spokesperson did not return a request for comment.

The Trump Justice Department has argued against a congressional subpoena seeking the testimony of former White House counsel Donald McGahn, claiming the ex-official has "absolute immunity" from such testimony because of his prior status as one of the president's closest advisers and "alter egos." That case is awaiting a ruling from the U.S. Court of Appeals for the D.C. Circuit.

Trump's lawyers with Consovoy McCarthy have also sued in the president's personal capacity to block congressional and Manhattan district attorney subpoenas for documents to third parties like Deutsche Bank. The U.S. Supreme Court will hear oral arguments in those cases next month.

But, if New York judges rule to let Zervos' case move forward, Hicks' return to the White House may present a new legal test for the litigious president.

Zervos' case focuses on Trump's conduct in the 2016 presidential campaign, when he called the former contestant and other women accusing him of sexual assault "liars."

Previously unsealed court filings in the federal case of Trump's ex-private attorney Michael Cohen showed prosecutors had evidence of Cohen being in touch with several Trump campaign officials, including Hicks, after the release of the "Access Hollywood" tape in October 2016. That video showed Trump bragging about groping and forcibly kissing women.

Because the timeline surrounds the 2016 campaign, that means the executive privilege claims Trump has invoked in other legal fights may not apply in this case.

Marc Kasowitz, the president's attorney in the suit, has argued in the Zervos case that Trump cannot face legal challenges while he's in office. "We believe that the Court of Appeals will agree that the U.S. Constitution bars state court actions while the President is in office," his firm said in a statement last month.

A five-judge panel on the Manhattan Supreme Court ruled in a 3-2 decision last year that Trump was not immune from state civil lawsuits while he is president, which allowed the Zervos case to move forward.

In September, Bronx Supreme Court Administrative Judge Doris Gonzalez ordered Trump to appear for a video deposition in a case claiming Trump Organization employees assaulted protesters outside Trump Tower in New York City in 2015, calling the president's testimony "indispensable."

But days later, Justice Dianne Renwick of the Appellate Division, First Department stayed Trump's video deposition as Kasowitz, who is also representing the president in that case, sought to appeal Gonzalez's ruling. A status conference for the trial is scheduled for March 13, according to court filings.

Michael Scarcella contributed to this report.